Working from purely direct exchange rate even if we remain at the vircurex.com rates(lets assume it allways remains at similar ratios)
Let me start, first of all there is next to no liquidity at the top rates.
Now to look at the top buy orders(not liquid at all)
5000DVC(1 DVC BLOCK) = 0.01515 BTC extra x 21.88 = 0.331482 BTC
24IOC(1 IOC BLOCK) = 0.004848 BTC extra x 264.92 = 1.28433216 BTC
96IXC(1 IXC BLOCK) = 0.02990784 BTC extra x 26.86 = 0.80332458 BTC
50NMC(1 NMC BLOCK) = 0.3556 BTC extra x 2.57 = 0.913892 BTC
So on average for every 50BTC you mine, you would end up with 53.33303074 BTC (~6.666% ie. extra 6.666% in earnings), this is all best case scenario since there is nowhere near enough volume on vircurex to assume these as realistic numbers, I would slice these extra earnings by 50% to atleast assume liquidity on the exchange.
So ultimately to answer your question, with us you would earn at current rate 110% PPS and with bitparking you would earn 97.5% + 6.666% = 104.166% PPS rate best case scenario and any miner with high volume would likely only earn at 100-102% at best.
So can you see that you have made a huge error in your calculations ?
My experience helps me side with you...wish it were easier to mine anything but BTC/NMC....
I think people like hitting all the buttons on BP...I did