Delta setup, Elevator stick difference manual vs acro mode

Pixhawk in fx61 running 3.8.5
Noticed that when in manual I have full range on elevator stick - so elevons move throughout full range of stick movement to limits, but in acro mode the elevons get to full range at about 60% stick movement in both directions (then rest of stick has no effect).
I calibrated the rc controls and from what I recall, this fixed the issue, but 2 flights later the same situation has arisen.

Sorry for sounding like a newbie! I need to re-calibrate again but thought I’d throw it out for discussion.

Acro mode controls your RATE of pitch. Your elevator input is translated into a pitch rate. Since your plane is not pitching up on the ground, the elevator continues to increase to achieve this pitch rate. Your PTCH2SRV_P and your ACRO_PITCH_RATE control the behavior the most.