So a little venting here. We recently bid 16 "fastfood" stores, installing electric vehicle charging stations about 3 per store. Our bids included a turn key install, including concrete removal and replacement, and with chargers supplied by owner. The project was prevailing wage. We recived a response saying we were 83% high. So your telling me a 30k job can be completed for 5.1k? Just frustrating with all the hours involved in the bid process for a response like that.
At that point my read would be you still have incomplete information. If your bid went to the GC, ime, they would just take 30% off my number and say without blinking, 'I already have a bid .7x'. I did not have that kind of money in the bid and would just walk out. When their regular guy was low I might get a call, you are x, everyone else is around you, my guy is .7 x, what did he miss.
There are some very low numbers at the base bid and if you go back later to see what they did, stuff I have seen I knew I could never break down so far as that to cheat so shamelessly on the quality of the work, omitting material, finessing changes. Lots of times the low guy is actually making low mistakes, for complicated stuff they cannot finish or the stuff does not run right. Often this is discovered way late or never. Quality of low bidders can be outrageously low. I very rarely see quality, splices in feeders and they still tear the nylon off the thhn on the wire pull, bolting onto busbars with cross theaded hardware, they install and leave stuff like that with no hesitation. Reuse of demoed damaged material.
That would be my suggestion. If you cannot talk directly to the competing low bidder for a chat, visit the job after they are done to see what they did and talk to the owners representative about their experience. Do they say nice things or claim they got screwed.
Surveyed one transformer room for a state critical data center. They knew they had problems but not what. No one would go in the room, they kept the door closed. All aluminum feeders at the trannys and they did not tighten the lug set screws. There were lengths of burned insulated wire at the lugs. No GEC's. I wrote it up. I told the manager it looked like the guy was hoping the computer would blink or hiccup when his name went through it. The raised floor area had lots of grey trough on the walls with scortch marks all over where they pinched the wire installing the covers. Stuff was in place baking.
Saw the same thing bidding in the town hall in a city an hour away. Took the main panel cover off and saw the Al feeders in the main lugs but not tightened. I put the cover back on, told them about it, and walked right out.
Sat at one bid opening to renovate 6000 sf corporate headquarters. We were told right at the bid we had 30 days no ifs ands or buts. I knew 90 to 120 days was more likely. GC bids go 145, 137, 152 and a big company bids 87. 45 days in the owner finds out everything they ordered, carpets, finishings, was another 60 days out and the job goes T and M for the GC. They stayed in there for two years and 1.4 mil renovating consecutive 5000 sf in sections at a time, probably all T + M, and changes, there were no other bidders after that.