The idea behind the Social Security Leveling Option is to provide an increased pension benefit to early retirees while they wait for Social Security Benefits to kick in. Once SS benefits commence (or generally speaking, at age 65), the pension stream would be lowered, thus keeping the retirees total retirement income stable both before and after Social Security begins. It should be noted that the pension leveling option is independent of any Social Security decisions. In other words, you could elect the pension leveling option and then take Social Security benefits as early as 62, or as late as 70.
I don't know if there are any SS leveling calculators out there, but that's a place to start.
I also think that if you die before SS kicks in and are married, your spouse is stuck with the reduced pension.
Not sure about your contract, but most firemen don't retire with medical. If you want to work, consider finding a job that covers medical into retirement. The company I worked for hired several retired firemen who were looking for medical coverage. They were usually hired as trainers, inspectors, even gardeners and security. They, like you, were in their 40's and had enough time to work and qualify for the medical portion of pension.
Here's a calculator that might help you out.