I have posted my opinion on tithing in the past. But I cannot recall ever linking directly to the discussion of the question by T.E. Peck (US Presbyterian, Southern, minister, professor of theology), and I would like to do so here:
Miscellanies of Rev. Thomas E. Peck ... - Thomas Ephraim Peck, Clement Read Vaughan - Google Books
Put simply, Peck's opinion changed mine from something closer to Pink's, to being in accord with his. I think it's worth your time considering his argument also.