Good news and bad news...
Somewhat recent excavator build benches 10% more on 1080/1080ti. I'm getting 2.2MH/s vs 2.02MH/s all things the same.
Can I see the settings of your 1080ti and miner?
Here you can see my latest settings for 1080ti yielding 2.02MH/s:
https://bitcointalk.org/index.php?topic=2765610.msg30101888#msg30101888Excavator in same exact conditions was ~8-10% faster, but less stable over time.