Being a type II, it may be that this clematis only blooms on old wood. This may explain why it only bloomed down low on the plant. If this is the case, it is way too early in your zone 6 garden to assume that it is finished blooming for this year. This year's growth should harden off and become old wood and you most likely will be rewarded with more blooms later on in the summer. Give it time before you decide that it is done for the season which is just starting in many zones.

Why do you have to prune it to get it out of the hole in your wooden fan trellis? Am I missing something in your description?

The part in the hole is an old, old stem so I wouldn't be able to cut it in order to free it from the trellis. I'm considering putting in a new trellis- that's the reason for the question.

There is no reason you cannot cut an old stem.

Your Clematis will most likely bloom again at the top on the new growth later this year.

Pruning it back hard was a good thing, didn't hurt it.

If Clems reach the top of a trellis you can let them cascade back down. won't hurt anything. If the trellis is falling apart, well then that is another story.