Dropping the ppm for bacon is your call. I personally would not. Here is a little background/perspective.
USDA requires Maximum of 120ppm on commercial bacon processors and requires the addition of an ascorbic acid. This is because of the fear of residual nitrite in the finished product, which if fried could form nitrosamines, which according to the state of California could cause cancer.
This is all because commercial bacon manufacturing is all completed in about 36 hours. This is from swinging carcass to cured, smoked, sliced and packaged bacon. Potentially there just isnt enough time to deplete all the nitrite, and since bacon is generally cooked at high heat there is a potential concern.
However, nitrite reduces quickly over time. For the home producer there is little difference between 120ppm and 156ppm. This is because we make a more artisan bacon product where we take our time to cure and equalize the belly. This time, is all that is needed to sufficiently reduce nitrite, something the commercial makers don’t have, time. No way they will or can take 14 days to make bacon, they would go broke.
If you are concerned about it, there are steps you can take to insure a safe product. The process is very important. I try to do my curing and smoke time in about a 14 day window then rest the smoked bacon about one additional week for equalization of smoke and flavors. Then slice and package. This extra time insures the depletion of nitrite but also produces a bacon with superior taste and texture. The other thing you can do is add sodium erythorbate to your cure mix, I do and really like the results. Plus it adds color fasting and reduces fat rancidity when frozen, really no down side to it and not an expensive addition. This erythorbate (NaE), which is the sodium of ascorbic acid or vitamin C, also accelerates the transformation of nitrite into nitric oxide, insuring complete nitrite depletion, but on the chance there is some remaining nitrite in the bacon when fried, the NaE stops the formation of nitrosamines.