When you send coins from v0.11.1 (64-bit)bitcoin core to an address with the highest recommended fee, is each confirmation dependent on the next (six I think in this case) blocks, or can there be more than a single confirmation in one block?
No. The 1st confirmation includes your block. Every further "confirmation" is just blocks on top of that block that contains your TX. The following blocks do not contain your transaction.
I ask only because I sent 1btc and got my 1st confirmation in about 5 minutes (still way too slow IMO)
Then sent 15 btc and it took 45 min. to get my 1st.
Mind you, one confirmation is good for me as I know it's on the network and will catch up in time.
The confirmation time has nothing to do with the amount of coins you transfer. The most important factor is the fee per byte.