I made that chart to show how the hosted mining services compare in fees. The S9 miner is most power efficient but Hashnest is making a profit on the fees they charge you, which is more than the power used by the miner. You will make more mining profit using an Avalon miner at POW88 than an S9 at Hashnest.
Well, I do not understand about mining, but I think having both is pretty good, because they both produce bitcoin. but, if the miner Avalon is better than the S9 at Hashnest, may very well hire Avalon miner in greater numbers. it might have the advantage that much in 24 hours.