Welp, whatever they gotta do to get those display casebacks to go down to 600m, they did it. With all the in-house movement craze going on they probably figured they need to show off their movements at any cost.
It appears there is an eccentric screw to adjust the hammers as seen from here:https://watchguy.co.uk/technical/Landeron/1472_Landeron 148.pdf
The only thing is its extremely tight and won't adjust either way. I really don't want to force anything on this movement as its otherwise very nice. Also the whole hammer assembly moves which makes it very difficult.
EDIT: It seems that its not an eccentric screw despite being in that table. Its just a screw with a tapered head. Regardless, it may be that the previous watchmaker was showing off feats of strength when putting this watch back together.