I like tree roses, but I shy away from them because of the winter protection issues. They take special procedures for wintering outside unless you have them in a large container that can be kept in a cold greenhouse about 35-40F for the winter.

Autumn Sunset and Westerland should repeat. I used to have Westerland, and it did bloom on and off all through the growing season. Have you dead-headed it? Have you fed and watered it adequately? Have you kept it healthy? All these issues influence the repeat flowering characteristics. Ambient temperature does influence a rose's growth, but Westerland is not as sensitive as are some other varieties. It should be reasonably okay.

My Autumn Sunset is gearing up for a (small) second flush.

My Autumn Sunset blooms almost continuously all summer. Even the one year old rooted cuttings I have in pots bloom repeatedly. I just keep the spent blooms cut off. Westerland does not bloom so well for me. It gives me a couple of flowers in spring but blooms rather sparsely after that, although a one year potted rooted cutting of it does bloom better.
It should be against the law to sell tree roses in zone 5. Unless you pot and overwinter as Bustopher says, tree roses in zone 5 end up as expensive annuals.
The only exception is Polar Joy. It's all one plant, no grafts, but it suckers freely. Well rooted suckers can be grown to be more tree roses, but they need lots of care once severed from the main plant until they get rooted well.
All other tree roses have the top graft which is prone to dying during our cold winters. It sets way up in the freezingg cold wind and ice. I've tried every method to overwinter them, to no avail. If they do survive, they go into a slow death spiral.
Save your money and put it into hardy shrub varieties. They can be just as attractive and require little or no winter protection.