My thought would be sort of like the Soviet Sniper: The Tiger Ace can only camo when:
- Not Moving
- In Vehicle cover (Such a value exist, I read about it somewhere on GameReplays)
Upon firing once, the Tiger would give it's position away, which would be the time to strike. You can also make the Tiger hold it's fire until attacking is at a perfect moment, giving a fitting ability to a more stealthy approach, stalking the enemy like the beast it is named after, however, naturally quick to escape from intense danger.
If you're worried about balance concern, you could make it's detection radius fairly high, so the camo only works well when hiding from a distance.
"Balancers are 10 a penny"