Yes JohnW2, but my question was to the OP and my answer to him sought to explain why there might be a difference between his estimate and the actual one.Whether the OP made a reasonable estimate of the total amount of time involved in all the activities and/or accounted for that time at a reasonable hourly/daily rate, I haven't a clue.
To the OP there will never be any consistency in quotes for numerous reasons. Not least because often the price is what the market will bear; different contractors have different overheads and sometimes and lets be frank here you get the vibes from your prospective customer that he is going to be a PIA and you price accordingly.
On the issue of consistency, I am currently getting a quotation for a new conservatory roof - one that has an insulated roof. I have had two quotes and helpfully each quote broke down the cost of having seven down lights and one ceiling light installed. One priced the job at £750 and the other at £500. As for the parts I asked for dimmable JCC FGLED6's which even at trade will cost me nearly £30 each - add the dimmer and the ceiling light gives you parts price of around £270. Each claimed that they were required to have the lighting work 'registered' with the LABC which bumped up the price considerably.
Obviously, that is not correct and will not explain the significant difference in price, so I will be doing that part of the work myself. But maybe its because I'm also a PIA.
But this example also perhaps explains one other factor the OP hasn't taken into account and that his builder will be making a profit off your use of his electrician.