Since it seems, salt was being consumed prior to reducing the BF time, perhaps your 11" high grid is equipped with holes that are too high from the bottom of the beer cup shaped legs, so water was no longer entering/exiting the legs to dissolve salt after the BF setting was reduced.
Suggest removing the salt from the brine tank to inspect where the holes are located, and if the existing holes are too high, drill additional holes through the sides, close to the bottom of each leg.
Although you will be normally utilizing and regenerating only 60K of the total 80K capacity possible for 2.5 ft3 of resin, the additional capacity greater than 60K is utilized to reduce hardness leakage through the resin bed. IOW, all 80K capacity is utilized to remove hardness, but capacity will be regenerated once 60K has been consumed.
Since no capacity had been regenerated for multiple cycles, all 80K grains of the resin's total capacity will have been exhausted. Now 80K grains capacity will need to be regenerated 1X to reduce hardness leakage and allow the softener to provide the softest water possible under normal use.
Because 50 lbs salt would be required to regenerate all 80K capacity, more than 16 gallons water would be needed. As 16 gallons all at once would likely cause the safety float to be lifted and also cause much of the dry salt to become wet and partially dissolved, suggest instead, use a bucket to add an additional 3 gallons water into the brine well, wait ~1 hour to allow additional salt to dissolve, then initiate a manual regeneration cycle. Once the 1st cycle has concluded, wait ~1 hr, then initiate a 2nd manual regeneration using only the water that automatically entered during the 1st cycle.. The 2nd regeneration could be started before you depart for bed.
The two regenerations back-to-back should substantially reduce the amount of hardness leakage that is currently occuring.
