The downside to that approach is that you have to do five sales (at 15-30 mins each) rather than just one to get a full Bunker's worth. Apart from the cost to your time, when you're selling, the Bunker isn't producing stock.
I buy 75k of supplies and sell at 210k. All delivery methods are easily doable using this method, although the dune fav sell mission is always horrible to do.
Compare that with the full bunker sale method, where you'll only take a small stock hit when going to creator then coming back to get a different delivery mission (that'll easily be doable solo).
I'm not sure how it works when it comes to how much you lose. I have only noticed it with slightly under 25% stock and with slightly less than 50%. In the first case i lost 1 unit(of which there are 100 in a full bunker). And with the second one i lost 2 units. That means that it would have taken me 7 or 14 minutes respectively to get that back(plus the cost of supplies for it). If that trend carries on up then with a full bunker you will lose close to an hour just to exit a sale. If we are lucky and it stays at 2 units then you still lose 14 minutes which is the same as you get with a usual sale with one vehicle. And that is given that the next mission is one of the 2 you can do solo.
It is a balance and personal preference thing. With a full bunker you risk(if you get the wrong mission) losing product which is both time and money. With a one vehicle sale you only pause production for as long as the sale lasts. Which for the Phantom Wedge, black insurgent and Marshall is usually less than 5 minutes.
This is in no way, shape or form an attempt to undermine the strategy by the OP or you. Your tactic could be the most effective overall but there are a lot of things to consider.