I haven't studied the remakes in any way, but I find the fact that a 1-5ms delay is perceptible impossible to believe.
I will say you can absolutely see a 40ms delay. Experimented with that on TSPP for a bit when we were worried about hitting all 5 flippers at once resetting the game.
But, 1-5ms is crazy, and the reason is every WPC game ever made. Service time on APPLE games' flippers was every 4ms. No one says Williams games shoot like shit.
Whitestar, SAM, and JJP (NFI about Spike) games service flippers every ms. That makes things like tap passes easier (the MUCH HIGHER coil strength does not aid that, however), tip passes easier, probably other stuff too. Much easier than Wms games. But other than those extremely finely-timed moves, you are not going to notice a difference at that level.
Whatever's going on with the remakes, it mostly likely has to do with whatever (bad) interpolation they're doing translating game logic directives into hardware firings. Again, I have no knowledge of what's inside or what they're trying, but all you have to do is look at the blinking of the lights (variable brightness on "off" blinking lights) on their games to realize whatever they're doing is stupid and wrong.
EDIT TO ADD: You're always going to see some difference flip-to-flip because of zero cross unless you have an awesome power supply or lots of caps or something. Power has different strengths as it moves along the sine wave of difference from 0-point, so where you catch it on that waveform matters.