I brought this up when I first drew the grenade, saying that the description of grenades in Basic (as this one seems to be that listing rather than a specific HT one) just says "between 2 and 4 seconds" and given we've otherwise been going on the side of speed and aggression with our explosives (see modifying our launcher setup to not have the short-range safety lock) 2 seconds seemed plausible for us to have. Nobody said anything and the GM's responses seemed to fit my understanding, but if we're going for 4-second fuses on everything then yes, the plan will change.