2 schools of thought
No doubt you have found a style that works for you, the tune of your rig, and the shape of your main. There are a few classes where this works as well as with the more standard method-T-10's have the top part of the fleet split between trav/down sheet on- then off (after you run out of trav) and simply easing the sheet first from a less than fully lowered position (maybe midpoint).
Twist is created anytime you ease some mainsheet- regardless of where the trav is. There a VERY few racers of sport boats, or any modern race boats who actually raise the traveller as the breeze builds-at least not near the tops of these fleets (J 105, M 24, etc.), but I know there are some who do prefer, as you say, to twist the top off before lowering the trav all the way.
It is also posible to use leech tension with low trav (while having opened the angle of attack for depowering) to maintain pointing and it works as well as having the bottom part of the sail "working" with some trav partly up while twisting off the top sooner-both can work, but I think the majority of folks who do this are as I said before, compensating for an overly deep mainsail, or in the case of T-10's the differences are because some of the sail designs from some of the sailmakers require a very different rig tune than others-(less prebend, softer lowers), which makes "blading" the main with full backstay harder, and so they indeed have the trouble you describe so well with the trav all the way down. But most of the top boats with North or Doyle or Q sails (again this is all upwind sailing related) do not ease the sheet more than a few inches here and there for the purpose of depowering, preferring to play the trav up and down in the puffs as a quicker way to stay on theor feet while maintaining point, and then go for the big twist after they need even more depowering after having the trav low. Again the biggest difference is in that they are not actually RAISING the trav as they approach overpowering conditions, but moving for more sheet ease before going all the way.
The other thing on many modern boats is the need to really limit flogging the sail-which really hurts the life of the sail-the former approach helps with this.
Finally, reefing, especially on large mainsail boats (racing-not cruisng) is the very last thing you do-and only when you have run out of small jibs (already down to the littlest), and lead adjustment for the sail (lead full aft). Once you reef the main, you lose a huge amount of point (relative to those who do not), and in some types, rig support is compromised to some degree. Look at the tuning guides for the M24, J 105/109, B 36.7, and any Farr design (Farr 40, Farr 395), and Farr is almost fanatical about not reefing-it the case of the Farr 40, he insists no reefs until close to 40 knots TWS-more wind than I prefer to sail in with a full main, but with the right jibs and crew weight, it IS faster..
But at the end of the day, if it works for you for whatever reason, go with it.
You will find if you ask 10 sailors how to accomplish the same task, you will get 11 answers.
In applying this approach for the 28, my feelings come from sailing the prototype while I was working at the E-factory, later as a sailmaker, and now as one of the North U coaches (part time) teaching the syllabus. This does not mean the approach is definitively correct, but it is certainly the more typical approach, and has the credibiltiy of being used by more top sailors than not (for their boats). They are both legit methods for meeting this objective-based on the variables they deal with on specific boat/sail/rig combos..
Cheers,S