Actually if you look at RPM indicators in 262 and you 'slam' the throttle you can see that the spool up or spool down time (response) of the Jumos is very slow so as you can right now figure out yourself right now HTC does not simulate blowing off the engines because they do model gentle handling with the throttles
The RPM rise and fall rates of the 262 represent how fast the engine would physically spool up or down, as if a rate limiter were applied to the pilot's throttle setting. It doesn't model the pilot gently handling the throttles, because the
player doesn't have to worry about it -- they just slam the throttle to the firewall and back and ignore it, relegating an aspect of flying the plane that was
crucial to its limitations in combat to an ignorable sideshow; you know that you push the throttle and you get your power sometime later, but you don't have to pay any attention to it beyond that.
Of course, if the throttle touchiness of the 262
were to be modelled, its perk value should be reduced, as it would be much easier for a pilot to casually pork his own plane by mishandling the throttle.