Actually as was brought to my attention in a previous thread weapon repair is intimately related to weapon price. That indeed is the reason for my unexpectedly long short sword repair. However I do not suppose there is too much more to say for this thread.
Certainly I have faith that things are done to improve the game and unintentional consequences are dealt with as they come up.
Just in case it helps someone the looted modified weapons seem to have had the new prices erratically. Some seem absurdly expensive: a Copper(?) Light Claymore was valued at over 5000 tria, it weighed less than normal but hit about the same, while others seem relatively cheap: an embossed broad sword was valued at about 320 tria and did about half again as much damage as a normal one.