Without seeing the house I'd have to say the equipment sounds BIG.
The point of COMPREHENSIVE assessment is to do a current and an IMPROVED load calc (missed by some HVAC contractors just getting into weatherization, they don't yet believe what a little air sealing will do, and they'd rather err on the side of too big because "Clammy" isn't an unpaid phone call they have to listen to, "Not cooling from 140 to 63 in 10 minutes" is).
If I take you HERE we can put in 40mbtu/1.5 ton:
I had a nice retired couple, wanted a quiet furnace for their 17 year old 1700 sf double wide. So I found the smallest MH rated furnace and set about playing with Infiltration until I saw where I needed to take the home so that furnace would work.
Took the home from 3000 cfm50 to just over 2000. Target for the calc was 2200. 1.5 ton heat pump, which we lock out at 40f because supply temps start to become uncomfortable. NBD as they are on Natural Gas (or I would have put in 2 ton)
Comments: the house is much more comfortable, much more even temperatures throughout (replaced 84mbtu/2.5 ton), and energy bill? Down about 35%. (She sends me pictures of her meter - it's in my blog as Ken & Karen.)
Aggressive downsizing does mean you can't set the thermostat back when temperatures get to extremes. But who really wants to do that anyway?