Dtps. vs Phal.?
 

I know that Doritaenopsis has been reclassified as Phal, so does that mean that I can change my Dtps. labels to Phal.?

You can if you like. You don't have to. :)

Is there a problem with doing that though? I read somewhere that there might end up being repeats of names that aren't the same cross...

There is that ... I have a Lc CG Roebling (gaskelliana x purpurata), which due to recategorizing of purpurata is now C. CG Roebling, making two with that name (the other is harrisoniana x mendelii)

I think it's only important if you plan to breed the plant. If you are not then I would not bother. This reclassification happens fairly regularly and causes all kinds of problems. I have a plant that is labeled Phrag. Grande. At that time one of the parents was caudatum v wallisii. Years later caudatum v wallisii was changed to wallisii, and crosses were registered as Paul Eugene Conroy. So what do I really have Grande or Paul Eugene Conroy? Does your head hurt yet? :)

DNA testing is changing the orchids names around somewhat. Eventually we will catch up to all the plants and give them proper names.
Im of the thought that the tag I bought with the plant is valid. When and if I take it to a judges meeting or a show then it should be properly tagged and displayed with the new name assignment(s).