If in doubt, there should be no doubt. Remember, nobody gets killed because you do ask for a further de/anti ice. It doesn't always work in reverse.
I've had days where I saw the only aircraft not to de-ice, but I did ask for an inspection. We were just lucky, due to positioning and the gap in the terminals compared to aircraft alongside us. Didn't need it and all was OK. They chose to, mainly I suspect because others a few stands from us had called for it. Not a problem. I had days where I was the only one asking for it too. Just have the confidence to ask when you need it. You seem to have good awareness so that's good. Like all of us, we seem to be more worried of covering our butts from the Ops manuals rather than anything else nowadays.
Happy flying.