To be honest, this is something I could get behind. What I understand you are trying to argue for, is that upon buying battle bonus, the initial cooldown that you have exhausted doesn't just go away. It continues counting down so if you play another match in the mean time and use your paid battle bonus, it will be possible that by the time you exit the match, your inherent unpaid battle bonus will have come off cooldown. This would make it much more viable for players without elite status to consistantly buy battle bonus while still getting something back in credits.
With the current system, it was argued that you could switch back and forth between fleets to get your battle bonus back faster if you didn't want to pay. However, at least from my experience, there really hasn't been any reason to do so. Once you have gotten a Tier 4 ship, and have veteran status on all of your Recruit ships, you gain nothing other than maybe 1000 credits at most by playing a game in recruit unless you want to pay to transfer to Free XP off your recruit ships. Ship XP earned on those ships cannot be used to help level the later tiers (without paying to transfer to free XP as previously mentioned), and the credit/free xp rewards are insignificant when compared to what you could earn by playing Veteran even without battle bonus. While I understand that in a free to play game, the game supports itself specifically by pushing players to spend money on in-game currency and items, there really just doesn't seem to be a point to the system that the developers have pushed for switching back and forth in fleets to renew battle bonus.
Thus, unless a change to make playing your various fleets more meaningful when you have nothing left to grind in them gets implimented, allowing players to not have to purchase battle bonus absolutely every time in order to just stay in a fleet would be nice.