timer multipliers:
1) army size (separate for each side) (A)
2) hero stats (from 1 to 2-2.5) (P)
3) date (D)
4)...
the main time bank for each battle is calculated anew, nothing is added to it
the secondary time bank for the round (not for the unit*) also depends on the army; for 7 units, it's 1-2 minutes, and then a multiplier based on the army size (calculated by HP or value, or something else). If the round time runs out, an emergency time of 11-15 (?) seconds is given to each remaining unit, and if it still doesn't end, it defaults.
approximate calculation:
1) a battle between two scouts with 7 units each on both sides
main time bank T*A*P*D = 5*1*1*1 = 5 minutes
additional time for rounds also (1-2)min*1*1*1 = (1-2) minutes
time per unit turn if both times run out 11-15 seconds
2) a full-fledged battle with 20+ units on each side, armies of 20+ ducks, 5 angels, etc., with stats of 15, date 13-14
main time bank T*A*P*D = 5*2*2*2 = 40 minutes
*additional time for rounds (1-2)min*2*2*2 = 8-16 minutes
time per unit turn if both times run out 20 (?) seconds
P.S. the multiplier for round time = the multiplier of the main bank (APD)*0.6...0.8