Ok, let's use the example of David A Oopser.
Dave attained seniority May 2018. He was making $18.75, then, come August 1st he makes $21.00 because of the language saying he gets the increases, but not less than what he is entitled to per section 2.
The language says the gwi is per contract year, and does not give a date the gwi is to be paid. UPS has to give everyone the increases in the contract as of August 1st 2018 per the agreement with the union, hence the retro checks.
Now, May 2019 swings around, Dave gets bumped up to his new progression rate of $23 per hour. He has now had two increases in the same contract year, which more than satisfies the gwi requirement for year one of the contract. August 1st 2019 rolls around, he gets gwi again, right? According to what? There is no date for the gwi in the contract. As long as his progression bump the following May satisfies the gwi amount and is no less than what he is owed according to the progression schedule, he has gotten what he is entitled to for contract year 2. And so on until he tops out.
Everyone else gets the gwi August 1st because they are already topped out, and that was the date of the original gwi for the new contract. Two contracts back they split the gwi and had dates for each raise, that was the last time the language supports the idea of gwi as well as progression. The dates were taken out last contract, and gwi continued to be paid out August 1st establishing precedent for that date. What there is no precedent for is gwi as well as progression, and the language certainly does not support gwi on top of progression.
The language states:
"Section 1. Full-time Wage Increases All full-time employees who have attained seniority as of August 1, 2018 will receive the following general wage increases for each contract year."
It does not say the increases must be paid out August 1st, just for each contract year.