Mitt's Tax Sheltering

There are various speculations as to the reason(s) for MItt's refusal to release his prior tax returns - from perhaps legal (but morally reprehensible) tax evasion, to drawing attention to the whole Mormon thing he's successfully avoided thus far (since his cult church tithing will appear on his returns) to not only morally reprehensible but also illegal mechanisms for hiding income from taxation. I, however, would posit an additional possibility which still involves sheltering his income but from the MoMo Church rather than from the IRS.

We can quibble about whether or not church tithing should be allowed as a charitable contribution deduction  (not a chance in hell [or whatever planet bad mormons go to when the die] in my opinion) but is Mittens really contributing a full 10% or only 10% of that which he is reporting to the IRS? Or, perhaps regardless of how you calculate it - he's giving nowhere near 10%.  Perhaps Mitt isn't quite the good MoMo he's perceived to be - it's one thing to cheat the Feds (and consequently the American citizenry at large) but to cheat Joe (seriously, Joe Smith? how fuckin' creative), the cult church and all of those little white-shirted, black-tied proselytizers and their families ... quite another matter.