If we compare the +25% rule to AMOS and STRIX I get the feeling that it's too high. Neither AMOS nor STRIX currently get any additional HEK bonus.
Swedish OOB (obat66, v. 5.5)
120mm AMOS
ACC: 6
HEK: 19
120mm STRIX
ACC: 10
HEK: 19
120mm Mortar
ACC: 3
HEK: 19
81mm Mortar
Acc: 3
HEK: 11
The fact that AMOS and STRIX rounds can be fired to hit simultaneously does not IMO seem to be reflected in the OOB. +2 might be reasonable for intelligent munitions all around with maybe some additional bonuses for big calibers. How about for every additional 10 HEK units (without VT) there's a +2 bonus with VT munitions?
Howitzers etc., typical HEK (base) for mm, proposed addition, new HEK for VT and similar improved munitions
Code:
mm base add hek
105 11 2 13
115 13 2 15
130 17 2 19
140 19 2 21
152 21 4 25
165 23 4 27
175 25 4 29
180 27 4 31
203 31 6 37
210 33 6 39
280 47 8 55
290 49 8 57
For mortars, 60mm might not be getting +2, but +1 instead as the HEK is quite low.
Mortars, typical HEK (base) for mm, proposed addition, new HEK for VT and similar improved munitions
Code:
mm base add hek
60 7 1 8
81 11 2 13
98 13 2 15
107 15 2 17
120 19 2 21
160 27 6 33
240 43 8 51