Umm, no, there were not always TPU's. There was always a trading power, and its dynamics were different in many ways than TPU's which some of us prefer to call ''points lite''
In the old 45 day window, all trading power was turned off at that point and any week you had on deposit would get any week availible. Then factors of quality filters were applied to the 45 day window, which perhaps made some sense. After that, however RCI began a steady process of downgrading the 45 day window, first by diverting inventory to rentals and to Points members, reducing the pool for Weeks members. Then, it became apparent that some, generally better, inventory never was put into the 45 day inventory at all.
When RCI took the two page spread promoting the 45 day window, which had been there for many years, out of its directory, the decline of the 45 day window increased. It is now so unreliable, that trading in the 45 day window is simply no longer viable.
There were always TPUs - they just weren't transparent before. Generally speaking, TPU costs do drop off significantly somewhere around 30-45 days in advance, although for some resorts it can be later or not at all. There is no longer an internal preference for Wyndham deposits, which is what allowed you to pull the Wyndham units previously. I think the 28Ks have a value of approximately 8 TPUs. You probably won't find much available yet for August at 8 TPUs but you should be able to pull more later. If you know where you want to go, set up an ongoing search. When/if TPU cost drops, it can match for you. I would still recommend checking the inventory yourself though, as there have been reported bugs with the ongoing searches. If you find a unit you want, put it on hold and then call in and see if a rep can get it with one of your 28k deposits.