In games with attack by percentage on, if you make an attack, it automatically assumes you want to attack with 100% percentage. If you want to attack with specific amount of troops, you have to change the number in attack amount. Is there a setting which makes attack by given amount of troops the default option?

I like doing my orders like:
1) deploy 2 troops on territory A
2) attack territory B
3) deploy another 3 troops on A
4) attack territory C

Which without percentage basically switches the 1st and 3rd order and carries that.
With percentage, the game attacks B with 5 troops.

In games with attack by percentage on

Not true.

In games with Multi-Attack, using % for attacks is the default. On all other modes having attack by % enabled you have to manually turn it into a %-attack.

As a little shortcut, if you dont want to enable or disable the attack-by-% manually you can type either the number of armies or the %, WZ will select the correct mode automatically