Having flown both types I am pretty confident in easily achieving a fix time +/- 5 seconds or so. I don’t have to, of course, but I choose to out of respect for my fellow airmen and the long suffering controllers.
That ATC has subscribed to the odd notion of central control is not the controllers’ fault, nor ours. It would be so much easier if a metering fix crossing time was part of our initial clearance. Why, pray tell, does ATC waste resources trying to predict crossing times when they could simply assign them hours prior, and let punitive holding be the wages of sin (or poor nav skills)?