It first appraised for $330k which I challenged as I had better comps, but it's rare to win one. 

The house still appraised for over sale price but I was wondering if this could be used as a negotiation moment or am I SOL? 

Search the BP for ADU appraisals to encounter numerous examples.

I thought better to terminate in the middle of repairs prior to them completing everything + Owe appraisal fees to Lender.  

Purchase price is 500K + a 25K concession, provided the property can appraise for 525K.

Appraisal came in 115k higher than purchase price.

I would have saved few thousand dollars in inspection fees and appraisal fees if I had known that and I had a friend send me detailed videos.I'm not sure if this information is available in all counties but where I bought in the Indianapolis metro area, I can look up property tax records.

Now remember, wife as MAI Appraiser, I have seen these bonkers 3.25 cap's and we both just shake our head's saying "what in the hell are they thinking?".

It's one packet, and they will have an appraisal.

My Atlanta property appraised for $320k and I owe $65k at 6 1/2% ARM (with 1% cap/yr).