All this is done knowing from start to convert loan to equity and further to also issue shares at premium compared to avg acquisition cost of promoters as you rightly mentioned. That is the outlook when looked from promoter's perspective.
Now look at non promoters perspective, or from just normal market participants and retailers. They never had shares from start, they never gave any loan so they wouldn't need to convert loan to equity and hence no bonus shares.
The valuer values the shares for the company as a whole and not separately for promoter or for non-promoters. Inherently the bonus is done to lower the avg cost for promoters, but that does not invalidate the valuation exercise done earlier, does it?
Awaiting your insights !!
@nbachoo