These last two provisions are rules in the Social Security system that I call "gotchas." Do both of the following apply to you?
If these two situations apply to you, then you are subject to the Windfall Elimination Provision and the Government Pension Offset of Social Security. Effectively, these provisions serve to reduce your Social Security benefits and to reduce or eliminate possible spousal or survivor's benefits that you might have otherwise received.
If you are subject to these provisions, then you might as well throw your annual benefit statement from Social Security in the circular file (aka "the trash"). It's not going to be correct.
To get the right numbers, you need your earning's history, your pension benefit, and a few other pieces of information. If you're interested, drop me a note and I can run the numbers to show you where you really stand.