Pumpjacks not producing correct amounts

After seeing players complain about their level 10 pumpjacks not producing as much as previous wipes I thought I would look into as even I thought its wasn't producing right.

So I got a level 10 and compaired it with a level 5 and you would expect that at the end of a period of time the level 10 will have double what the 5 produces. However this is not the case the level 5 is actually producing a little more faster than what the level 10 is. The more time that passes the bigger the difference is.
eg. I would expect after a peroid of time a level 10 = 10k so a 5 = 5k but buy the time the level 10 reaches 10k then the level 5 has produces 6.5k

This is the case for both running them with and without pipes

EDIT: Everytime I pick up a pumpjack and replace it I get different results, sometimes in a 24 hour period it will produce 60k LGF other time little as 10K LGF. It is very inconsistant and with every day I get more and more complaints about it.