Below is district pay for various Portland-area districts for the 2021-2022 school year. All credit bumps start with a Masters (so, the 15 credits line is actually the MA+15 salary schedule).
Note that different districts give pay bumps for different credits post-degree. For instance, PPS teachers bump to the next line every 15 credits after their MA, whereas WLW teachers jump at MA+24 and MA+45.
Additionally, PPS teachers get an additional $2,000 for a relevant doctorate, which is not shown here.
Here is the same data, showing only the 0 credits post-MA lines to enable direct comparisons.
Below is a plot showing just the maximum achievable pay for each district and credit level. Note again that the maximum for PPS with a doctorate will be $2,000 higher.