I think Skipper is heading the right direction.  You can argue tithing all day and still not agree.  The reason is people like legalism.  It's much easier to draw a line and when you cross it say "OK, I've done my part." I've been told when you total up the tithes and offerings the Jewish people were required to make we read about in the old testament it was closer to 28%.  But back on topic.

A friend and I have discussed this a lot over the years.  He says his business does not have a 10% margin, so if he gave 10% gross he would go broke.  This is where the increas comes in.  The tithe should be on what your increase is.  Which begs the question, "What is my  increase?"

Here's what we finally decided to do. I'm not saying it is right or something else is wrong, it is just how we do it. (Note we are a proprietorship, not a corporation)  We have a farm checking account we pay the business expenses from.  We have a family account we pay the family expenses from.  When we transfer money from the farm account to the family account we tithe on that amount.

I don't believe God is an accountant.  He isn't setting there going "You transferred $142 and only gave $14"  It is about your heart.  There may be times whenn you cannot tithe.  A friend went through bankruptcy.  I won't go into details other than someone failed to pay them what they were due and were forced into bankruptcy.  But because of it there was a time they could not tithe.  It really bothered them.  That is what I think God is worried about, where your heart is.

Gotta run, the cook is standing here with her coat in her hand saying "Ready Yet?"  Later Y'all