Ac not keeping up

Context: full system replacement done last week. 2 stage variable furnace, ac, Cased coil, line set. Rheem system

Was 2 ton, 60kbtu furnace

Replaced with 2 ton 60btu furnace. No issues with old system.... customer reached out asking to update it... knowing it was old. (26 years)

Set up and run tests completed on install.

Received a call 2 days later, system runs constantly, never meeting the 72 degree set point except at night. (OAT 85 highs, 75 night).

Went back to test further

9deg SC, 12deg SH, but low saturation (around 38deg)

Indoor set temp 70, keeping 72

Return temp at unit were 66-67 degrees

50%RH 19deg split

Figured maybe a capacity thing with the low ra temps. Increased airflow to 920 from 790

Same complaint 2 days later. It runs constantly. Set to 72 and usually is sitting just shy of it.

Why would I have a capacity issue? What should I do to rectify it.

Is a2l that much lower s capacity? Are they marketing these as 2 tons even though they might only me 21kbtu or something?