Ok, let me see if I understand this correctly.
1) You approve the Ivy prelim, but after the piece is finished, THEN decide you really don't like it.
2) Tim offers to try again on the piece (for no other reason than he's being a nice guy about it as you DID approve the first prelim)
3) You offer Tim some extra $$ for the first effort (kudos to you) which he didn't ask for (we'll come back to this later).
4) He tries again on the Ivy, something which looks pretty different from the first effort, which you up front say you don't like.
5) Tim decides that the time to effort ratio on that piece may not be worth his time as this is now two strikes on the character (ok, this one can go either way on if it's right or wrong).
6) Tim says he'll give you the three pieces you already like for discounted rates and forget the Ivy.
7) You wonder why he's throwing it in your face that he gave you a discount, which is really no different from your explaining to us how you were "giving money away" when you gave him some extra money??
8) Finally, when you decide that because he's not willing to bend over backwards for you for $60, you don't want to pay for ANY of the work he's already done, that you approved, and you said you liked, he's the unprofessional one in the transaction and he alone??