You see it and hear it all the time. What is the last word when it comes to the rules of AD&D 1E?
Many people want to say that since the Players Handbook came out before the Dungeon masters Guide that it set precedent and always look to corroborate things that are said in the DMG against it.
To me and quite a few other people I have discussed this topic with, the DMG was written to stake out for the DM, what may have only been lightly addressed nand even not addressed at all in the PHB.
I am fine with accepting the DMG as the last word on the written rules. This goes hand in hand with the notion, as written by Gary Gygax, that the DM is the final arbiter. Hence, the DMG would be the last word on the written rules with the DM obviously taking that as far as he/she wants it to go.
Having said that, if the DM decided they preferred to let the PHB have the say so of the written rule, that's their choice to over rule the DMG in that way. As intended though, I think the DMG is the "default" stop point.
Personally, I do not accept later publications like Unearthed Arcana or magazine articles,etc.. as anything more than options that may or may not be taken up by a DM if he/she desires to add them in.
The DMG has spoken. Long Live the DMG!