Here's my take, you were granted SSI because you were poor and disabled AND had not worked long enough to qualify for SSDI. (To get SSDI, you don't have to be poor. If he were too disabled to work, Brad Pitt could get SSDI. You just have to be too disabled to sustain "substantial gainful" employment, which means able to earn over $1,090 per month.) However, if you keep working and earning over $500 per month for another 8 months, you will finish earning the needed "work credits" to qualify for SSDI.

Once you get SSDI, you may or may not keep getting SSI. It all depends on the size of your SSDI check. If your SSDI check is just as big as the SSI check that you've been getting, then you won't be getting anymore SSI checks because the SSDI check will completely replace the SSI check. However, if the SSDI check is smaller than the SSI check that you were receiving, then you will still get an SSI check big enough to bring your income up to what it was when all you got was SSI.

The SSA employee has figured out that your earnings were small enough, or your time in the workforce has been small enough, that your SSDI check is going to be smaller than the SSI check that you've been getting. So you will get some continued SSI income, but it will be smaller than what you've been getting.

Your SSI will not end before you get SSDI. Once you get SSDI, your SSI check will be reduced, but not to zero because your SSDI will be relatively small (less than the federal and/or state feel that you can live on.)

BTW - what is "MA?"