Our saws that are used commercially & are traded every 2 years, so the oil cost doesn't come into it,& we have to make a living from them so down time is a NoNo,whilst I admit to not being as active as I used to be I've been sawing in some form or other for the last 50 years & have now reached the tender age of 79 & to date ( according to my doc )although some bits are falling off; my hearing & lungs are still in good shape,I suppose it rests on how much you pay for your oil ? we get a FD rated 100% syn oil which we buy in bulk which works out at 2.40Euro's a litre,
another factor is how big is the wood being cut ( in other words how long is the saw being used ) running flat out; there are a lot of factors that enter into the equation? I'm not trying to tell anyone what they should /shouldn't do just noting in my view that nowadays there seems a move to use the least amount of oil possible, & have noticed more failures,that could have possibly been avoided by the use of a tiny amount more oil. But as you seem happy with the set up you have Safe sawing.