Using shingles to flatten concrete subfloor
I've done things like this on a number of occasions, and the problem is that you'll create more bumps than you resolve. Only the inner portion of your depressions measures 1/8", and fairly quickly they taper up to a smaller dimension. This means that the edges of your shingles are almost always too thick for their position. 

Also, they're crunchy. For at least a while after installation you'll hear it underfoot. 

You're much better off skimming with a leveling compound.