Fair enough, Eisey - the culture in my company re: FOQA/SESMA/OPTIC/whatever you call it does not result in cups of tea very often, unless it is very obvious that negligence is a factor. Instead it is used to identify operating trends (such as pilots flying below S speed etc) and permit safety management to either a) write a fleet memo saying DO or DON'T and/or b) change SOPs accordingly and hopefully also c) allow the training department to conduct proper training/explanation of the circumstances.
Individual pilots should not to be pulled out of the ranks unless something warrants serious re-training. If that is unfortunately the culture where you work, I am sorry.
Still doesn't change my suspicion that if the FOQA picks up when F1 is reselected after F2 extension, it would almost certainly pick up flying below S speed with only F1 selected, regardless of the rights and wrongs discussed here, since whilst still within the operational envelope (as agreed here) it falls outside most companies (and so I suspect also the manufacturer's) SOPs for airmanship reasons.
So if you really want to avoid a 'cup of tea', the (somewhat flippant but still valid) response has to be:
1) stick to your company SOPs, even when you think you have a 'better' idea
2) if your fellow crewmember (Captain OR First Officer) is unhappy with the reasoning behind a proposed deviation from SOP, you have a duty to keep them 'in the loop' and comfortable with the operation; so resist trying it on this occasion! In any case see rule 1)
3) Take your suggestion to your technical pilot/chief training captain for the definitive response and (if necessary) top cover - you might be thanked for it, or you might learn something.
This issue seems broadly split on technical validity, but ought to be considered also from airmanship and CRM terms, as mentioned.
All the best,
GL