sigh,thats why it depends on the servant and how many hits it can do,also you need to consider the first card bonus.
The first Command Card chosen gives all other normal attacks a bonus. Noble Phantasms do not get this bonus.
Quick - 20% increased Critical Star generation.
Arts - 100% increased to NP generation.
Buster - 50% increased damage.
Card Type
Quick
Arts
Buster
Order
1
2
3
1
2
3
1
2
3
Base Damage
80%
96%
112%
100%
120%
140%
150%
180%
210%
NP Gauge Rate
100%
150%
200%
300%
450%
600%
-
-
-
Crit Star Rate
80%
130%
180%
-
-
-
10%
15%
20%
Table taken from http://fategrandorder.wikia.com/wiki/Command_Cards
also if you use A-B-B, the B will give you +1% np charge