(warning, this is a pet peeve of mine, but I'm also an accountant so accurate numbers are important to me LOL!)
Dropping the leading 0 in the number is a very common mistake people make. I see this on eBay listings all the time!! and it can make a big different in the age as Singer used the G series from 1910 to 1924 and about 11 million machines.
If you look over the numbers, you'll see that Singer went up to 999,999 and then to 1,000,000 and then they ran out of numbers for the G series, so they jumped from 9,999,999 to 0,000,001 and went back up to 0,999,999. Then they jumped to AA. (Keep in mind, G and A# (two digits) were used in the Elisabethport factory, but who knows if that was exclusive)
And since Singer didn't put commas in, a lot of people will get the wrong number because they don't read all of the digits - or stop looking when they've matched up the first six digits and forget the seventh, and the difference can be 10 years if the number is 9,762,892 and matched as 976,289
BTW - this is why it's good to know what the models look like. There is no doubt this one is a Model 128, so if you look up on the chart and it says something different - it's time to go back and look more closer at the model number to make sure it was read correctly.