Been there before... Good news is that since your doing a PM, you can easily bump up the amount of extract and fix and the effiency issues you might have with the grains.
It can't hurt thats for sure. The only real way to tell is to do an iodine test to see if you are getting conversion, but if you can't do that, I'd say pull a sample of the wort out of the mash and check the gravity to ensure you are getting something out of it.