I've always used "4" to force limits the same way.  I don't have P7, but they did make a change in P6.  The parameter is now "1."  It will still respect "4," but will change it to "1" on saving back to the library.  "1" works the same as "4" in earlier versions.

Perhaps they made a further change in P7.  May need to use "1" now.

John