" ..but recent properties have been selling in the high 80's and low 90's .."
Anyone can "ask" anything they want ... it's the "getting" part thats tough.
If you're comparing apples to apples (extras to extras) at the high 80's and low 90's, then you need to be coming in at the low to mid $80's, preferably the low low $80's.
See, the problem with most agents is very simple ... your emotions are way up, you're excited and the agent wants an easy deal and you're easier to negotiate with than the sellers agent or the seller, they love that scenario -- the problem is, it doesn't help you one little bit.
If you've truly done your homework and you feel your figures are correct, then you need a figure to arrive at, not a figure to reach past, and that just takes a little negotiating ..... don't be timid, give your agent the figure "You" feel comfortable with, not what "They" feel comfortable with ...
If the sellers agent is worth anything they'll come back with a counter and thats when the real negotiations really start ...
Hmm, let's see -- it's winter, aah you live in Pittsburgh, it's dark and cold and you probably won't see spring til' May, the seller is going uphill for the next 4 months.
If you feel uncomfortable with whats going on, get the agents together with the seller and you negotiate your own deal with everyone present - I've done it many times and saved tons.! .. most agents aren't very strong when it comes to face to face or any real "table time".
Good luck, and you can do this.!