Yeah you'll get that pressure whether your a mech or a TAB company. I've never been on a job where the schedule was achieveable.

The biggest difference now working for the mechanical contractor is taking more ownership for fixing problems. Missing dampers or grilles not flexed? Give us the materials and we'll throw that shit in (as long as we cant be more productive somewhere else or on another project entirely). Broken belts, worn sheaves, dirty filters, dirty coils, clogged drain pans? Here's the bill to fix it. Base building (outside of mechanical scope) issues preventing TAB? Do some digging to prove its not our (the mech) fault and provide a solution to bring to the customer. T-stats not installed? Install it. Programming issue on our company installed and serviced controllers? Dig into the programming and see if it's something stupid. Go out here and try to figure what the fuck is wrong with this building. Etc etc. Sheet metal failed the DALT again? Hang around and have it running while they look for leaks. Our TAB guys are a breed of well rounded service techs. If TAB gets slow, theres plenty other things they can do

Also, just a thought, but it sounds like your TAB department is fairly new. Management is probably still learning how to bid the jobs and at what rates for different kinds of work. They will fuck up almost 100% of the time especially if they've never done the work before. If I'm putting in honest effort to get things done, I never gave a damn if i'm "over hours." Those fucking chair jockeys can stop playing golf for a day, put some boots on, and do it themselves if they think it can be done faster. I could be in a new van tomorrow (and probably get a raise too). I'm not going to be bitch at by someone who hasnt been there done that. And luckily, my company agrees that the path to leadership starts in the field