Question about yeast and total fermentation

I'm new to homebrewing, but am on my 6th batch. I started with a syrup kit, then progressed to all-grain. One of my AG batches took off great, and showed fermentation signs for over a week using safale 5 yeast. The most recent batch I used Muntons dry ale yeast beause the LHBS handed it to me. It showed signs of fermentation for the first 48 hours then all the krausen disappeared and it is just sitting there. I have no problems letting it sit for a few weeks, but...
I looked up the yeast on muntons website and it says it is not good for all grain because it doesn't ferment the more complicated sugars.

My question, is should I repitch with a different yeast so I get full fermentation?

It's a good idea, but check the gravity first, because the attenuation will depend on your mash temperature.

Let it sit for about a week and take a hydro reading, see where that leaves you. . .then take it from there.