Good idea but won't work.
Pay bumps for higher certs will be negotiated between union and state and then specified in a matrix or chart as to what "counts" and what doesn't. I personally know a great teacher who self-improves but not always at "approved" venues and therefore doesn't see pay increases, points, higher rank, nothing. I also personnaly know another teacher who is just good - not great - but "games the system" and continually attends "approved" venues and gets pay bumps and teir increases all the time and yet never ever rises above "good" into "great". Once you specify a program of increased pay for increased credentials, all you do is create a "game" with "rules" for civil servant careerists to "play". And a cottage industry will spring up to support it - vendors, trainers, etc, to get a piece of the pie. none of it actually equates to more great teachers unfortunately.