Engine builders...this machining cost sound excessive?

Depends a ton on the area (the NE USA is gonna be expensive) and the shop and how established it is (machines paid for or not) and how they run things (clever at making tooling and has done most everything already, or need to buy everything). I'd pay far less that the OP, more like Kooser pays, but when Bill Mathias at Eastside Machine here retries, I expect to pay a lot more. So really there is no 'typical'.

And let's not forget the exchange rate to Canada; RAMM's rates will be roughly 30% lower in the US just based on the exchange rate now.