Good point. Though, from my recall, there isn't much basis in the OT for the modern day concept of tithing at all, percentage or otherwise. Christianity points to verses about giving 1/10th of your crops to the priest as the basis.

If they really wanted to change the rules and up it to 1/7th, or 12% or anything they want, they could come up with some new basis for that match using fancy hermeneutics.

This is sort of what is happening right now with homosexuality. Many churches are changing their views. They are justifying that by reinterpreting the verses they've used to condemn it in the past.

In fact, you can pretty much get the Bible to support any position or far-fetched belief you'd like. You only need a few verses... and it's a big book.

This is one of my favorites.