Tired of Flat Rate Pricing Eating Into My Electrical Profits?

Been doing electrical work out here in Arizona the past 10 years, and flat rate pricing on panel upgrades is starting to feel like a trap. I quoted a 200A service change last week using that standard book, figured it'd cover the 2 hours of trenching for the conduit run, but material costs for the Square D QO breakers shot up 15% since last season, leaving me with peanuts after the job. Customers love the upfront number, but when I hit snags like old aluminum wiring that needs remediation per NEC 110.14, I'm the one sweating the overrun. Switched a couple jobs to T&M at $95 an hour plus materials, and damn if it didn't net me 30% more without the haggling. Anyone else ditching flat rate for residential service calls? Feels like the only way to stay sane in this heat.

Flat rate screwed me on a similar panel swap last month, ended up eating $400 in unexpected grounding electrode costs just to pass inspection. Switched everything to T&M now and never looking back.