I must confess I’m a bit perplexed by GOP presidential nominee Mitt Romney’s continued refusal to release more of his personal income tax returns.

Just about every leading Republican is telling Romney to do so.

Now we’ll see how many years his VP pick, Rep. Paul Ryan, releases.

Most likely Ryan won’t release more than two years, if that. He won’t want to be showing up the boss, after all.

When a politician/candidate refuses to do something that all other candidates for the office he seeks have done, there are, of course, lots of questions.

And with Romney’s background in capital finance/investments, his tax returns are of greater interest than, say, if he’d been a congressman or governor for years on end.

Having financial accounts off shore doesn’t help Romney, either.

Now, last week Romney, who I got to know a bit while he was running the Salt Lake City Olympics and always found a nice guy, said that he himself had “looked over” his recent tax returns and it appears to him that every year for the last decade he’d paid “at least” 13 percent in taxes.

Thirteen percent?!

Now, I realize I’m just a dope who has worked for wages all my life. But my wife and I have paid more than 13 percent in taxes all our working lives, going on 40 years.

Being a dope, I haven’t been able to do my own taxes. My wife is more than smart enough to do it, but she’s so busy that we’ve opted to have an accountant do our taxes.

And on the cover page of each year’s filings is a letter from our accountant that lists, among other things, our effective tax rate for that filing.

I’m guessing that Romney’s taxes are a lot more difficult to calculate that those of the Bernick family. But I’m also guessing that somewhere on those dozens (if not hundreds of pages) that his accountants (he likely has more than one) produce is also listed his effective tax rate.

So I don’t see why Romney had to do his own calculations to come up with that “at least” 13 percent paid each of the last decade.

Anyway, if he has paid about the same tax rate since he was hanging out in Salt Lake City running the successful Olympics – which is about what he paid in the two year’s is releasing – then why doesn’t he just release the other eight years and be done with it?

Is he just really stubborn and he won’t do what all his opponents are telling him to do?

No, wait, even his supporters are telling him to do it.

So, I and a lot of other folks are wondering if it isn’t that he hasn’t paid any (or more likely, not much) tax in the last decade – that he really has paid “at least” 13 percent -- there must be some other reason.

Here’s my guess (and I stress it is only a guess).

Romney doesn’t want to release his taxes not because he hasn’t paid “at least” 13 percent over the last 10 years; it’s because he hasn’t paid “at least” 10 percent in tithing to his church – The Church of Jesus Christ of Latter-day Saints.

Now, I know that he’s paid something like $4.7 million in tithing over the last two years to the Mormon Church. That – assuming the 10 percent level – would be earning around $47 million in gross over those years.

Not bad for a guy who recently joked – even if it was a poor joke – that he was “unemployed.”

Many Americans may not understand why Romney, or any other Latter-day Saint, would be hesitant to release tax returns that showed they had not paid their church all that they may have intended, or believed, they had.

But those folks don’t understand the Mormon culture – especially the culture among the elite levels of the church, the area that Romney and his current family and his forebears have lived in their whole lives.

In the Mormon culture all kinds of blessings follow someone who pays his tithing and lives a life true to LDS beliefs.

One of the top leaders of the Mormon Church recently advised members to pay their tithing before they paid their mortgage, even if that meant there wasn’t enough money left over to pay their whole mortgage.

Live the true church life, pay your tithe, and material problems and challenges will, somehow, follow to a satisfactory conclusion, is that general authority’s advice.

This is serious stuff among LDS faithful society.

And if a faithful member is outed publicly as not paying a full 10 percent on all of his gross income, well, that puts that person, his family and his reputation on the line.

Now, honest people can make honest mistakes.

And with the income complexity of someone like Mitt Romney, it can be understood if he didn’t always pay a full 10 percent.

Maybe he missed a few years, paying 9.8 percent or 9.1 percent or some such.

But if he’s down around 7 percent or 8 percent or, Lord forgive (and He might have to) even 5 percent, then while the rest of conservative, non-Mormon voters may not care much, inside the LDS culture that Romney and his family moves that would be a big deal.

To put it bluntly, it would be an embarrassment – one that many Americans wouldn’t understand or care about, but one Romney doesn’t want to burden himself and those loved ones close to him with.

Romney could always go back and make up less-than-10-percent payments to his church.

But that would look fishy also – how come he didn’t know about the tithe shortfalls as he signed and was briefed on each year’s tax return?

In any case, it appears that Romney is willing, at least for now, to go through the rest of the 2012 campaign saying two year’s tax return disclosure is good enough.

He’s saying let’s talk about some real issues, like unemployment, the slacking economy and the federal deficit.

Who cares about tax returns?

But those returns contain something, apparently, that Mitt Romney doesn’t want to explain or talk about.

And we may never know exactly what that is.