That 30 ft away. Is that in a straight line or is that the path that the conduit will have to take? You don't often get to run conduit in a straight line from point A to point B especially when its enough conduit to feed an entire 400 amp panel. A couple of turns of the conduit and add the distance getting down from a high ceiling area and that 30 feet could easily be 50 ft. If that conduit length increases then so does the length of the wire in the conduit.If that's the mindset of all electricians, it's no wonder they can't be that good electricians. Thirty feet away, that's three sticks of conduit .
I think that electricians like a few details before giving an estimate because they are used to doing the work.