The advantage to dosing is you can get exact small amounts dosed equally over a 24 hour period. This helps stability. Set ups are not expensive and very compact. However as others mentioned you seem to be losing minimal alk and cal per month which water changes or simple hand dose balance out. Until your demand increases you are probably fine but if your corals are not growing you may have another underlying issue to resolve.
I have about 40 gallon volume in one of my tanks with about 20 sps frags and a 3 larger LPS and I go through that much in less than a week. I manually dose 15ml of 2 part daily. Have it sitting on the toilet tank so I remember to dose when I get up. I thought about a pump but figure it's not really worth it to me. How much do you need to dose daily to keep up with only 1. 5 dkh drop over a 6 week period? The amount required is what I would use to determine if it's worth using a pump.
I'm running it on a 65g system mixed reef, with heavy population of LPS. Its been rock solid for me over the past year.
Also wanted to mention, your system could be consuming large amounts of dkh/calcium due to precipitate in the sand or calcareous algae growth.
Honestly I'm probably just going to manually dose for now and test it once a week maybe every 2 just so I can compare to my trident and go from there. That way I can use that money for a recirculating skimmer and get it out of my sump and free up space in there for other stuff. Especially since the skimmer I was recommended for my tank is definitely too big and does absolutely nothing for my nutrients what so ever! The thing it's best at is be consistently inconsistent and filling the cup up and shutting off.