How does intel work ?

I put 3 military saboteurs in a rural province that has two main cities bordering and at daychange I seen what appeared to be his entire army, From all over his land and his navy.

But it did not show a a naval fleet of level three battleships it only showed a stack of seven with a few destroyers level one and a couple cruisers.

So I sent a stack of ten level 2 battleships to attack it as he had a few level 1 subs scattered around his shores but not close enough or enough of them to get to the fight in time as far as the intel appeared, when I got there it showed up as the 7 I seen on intel along with 10 level 3 battleships.

-Are battleships hidden from intel at a certain level ?

-Does intel sometimes reveal 80 percent of his units and not all of them for example ? ( Iknow sometimes I’ve revealed a stack in one province but this reveal looked like his whole army I seen stacks of troops on every border I seen subs all along the coast and the 7 stack naval fleet.