From the moment you spawn in to the first-hand battle, generally speaking. However, it's not out of the realm of possibility to use it twice, or thrice in one life. With a 75 second cooldown, it's going to be difficult to manage another ability activation, even with the Replenisher. It's an A class mech that doesn't specialize in killing, which is where you get the most benefit out of the Replenisher.
I was going to say the delay should be removed, but it having two effects seems to alleviate some of the balance, if this turns out to be true.