As shown by several examples in my bug report [here](< base_url >/index.php?/topic/21373-lasers-list-incorrect-overheat-and-cooldown-values/) the client seems to calculate the time to full overheating incorrectly.
To stick with the examples in that other thread, let’s look at a RF Blaster. Displayed stats are 250 RPM, 6 seconds to full overheating. Measured shots till full overheating are 25 as seen in the linked thread. From that it follows that the current calculation is as follows:
25 shots = 6 seconds/60 seconds/250 RPM = 6 / 0.24 seconds per shot
The problem is that this calculation ignores the fact that the first shot takes no time. The cooldown only applies to the next shot. Thus, to fire 25 shots does not take 25 * 0.24 seconds = 6 seconds as displayed in the client but rather 24 * 0.24 seconds = 5.76 seconds.
The same applies to other weapons, respectively.
Alternatively, if you say the displayed values are correct, then all weapons in game except lasers, which are broken anyway (see linked thread), should overheat only after one additional shot compared to how they currently overheat.