From experience the estimated build time is just a rough estimate. Had 2 factory build previously, one from Barcelona and one from Ghent, Belgium. Barcelona one was 'late' by 3 weeks, citing inavalibility of my 'special' colour choice, which was pulled the following week after I placed my order. They honoured the colour, but probably took some time to source it from another factory. The car from Ghent, annoyingly (the Barcelona sourced car was still around) arrived at the showroom a month early, so it sat there (probably it was also a showroom car to prospective buyers, as the boot led light bulb was non-existent! probably meant it was open for long periods of time). Now with Covid, all bets are off delivery time wise. I ordered my A3 Sport with C&S early Dec. I have no idea if it's built or when it would arrive to UK yet. Only one email from leaser that it won't make the original estimate of end Feb delivery. It's ok, I do not desperately need a car atm.
The fun part with the Barcelona car was that they gave the name of the ship it was coming on (big mistake haha), so there I was tracking the ship everyday, it took 6 days to get here from Barcelona, going first to Germany (maybe to drop off some Audi Q3s) and then it turned back to UK to drop off the cars inc mine!