Curiosity To Me - 2c Edward Single, Imperf But It's Type 1 And Used. Comments?

Found this in a decent Edward collection. If you observe the upper left where the spandrel meets the vignette oval, it's missing the frameline thus a Type 1. The margins suggest to me it's not trimmed from perforated. Yet, it's used, and the imperfs issued to the public were all Type 2, I thought.

Any experts out there able to chime in? Happy to hear opinions thanks. I realize it's a rather specialist question.

Unitrade lists 90iii as imperf, type I, although using one would be uncommon.

Actually, I have seen a few used, even on a flight cover.