Also, this is undesirable if the HIVE price was lower in the past, but has risen say in the past day or so, which will regularly happen due to typical price fluctuations. It will discourage creating new HBD even if HBD is overvalued and more is needed, since the minimum will take the lower price, not the current price, and the converter is penalized.

Now in this case, is is clearly no worse than simply not having the function at all (which is where we are now) so in that sense it can't be seen as an objection to the proposal.

But I see see no gain to using this proposed method over inverting the existing conversion mechanism, which has proven to be quite effective (apart from situations where the haircut is hit, which of course is a different issue).