So I'm getting a bid for AC & new furnace (22 year old furnace, adding AC)

It's a tight fit, and the guy doing the bid was doing a lot of measuring, and checking for fit for it.
But looking at the Carrier website for the parts he spec'd in the proposal, I'm thinking they're mismatched.

58CAV0701-12 Carrier furnace
38HDL036 Carrier 3ton 10SEER
3K5AXA036017 Carrier Coil,00.html

The installation will be a down-flow system.
It's in a tight space in the 2nd-floor, un-insulated space (roof comes down on that section of the house, making it only usable really for storage/mechanicals)

If I'm reading the above links correctly, the coil is 17", while the furnace is 14". So I'll have a furnace 3" narrower than the coil? Is that normal/acceptable?

I'm also concerned that he may be over-sizing the cooling system - I've got a 1200BTUh window AC that mostly cools the house. (cold in the upstairs room; OK to a little warm downstairs) Going from 1 ton to 3 ton seems like overkill.