Someone high up at the Singer plant must have been bad at math.
Fictional Singer Executive: There are too many 15s and customers are getting confused. Next time we will skip ahead a few numbers and leave empty ones in the middle instead of this 15-28 15-29 15-30 nonsense. Jump ahead one hundred and set aside 115 for a domestic model.
Fictional Singer Dictation Taker: Yes, sir. *writes*
Fictional Singer Executive: And jump ahead fifty and set aside 66 also.
Fictional Singer Dictation Taker: Sixty-six, sir?
...
Fictional Singer Executive: We want the customers to understand that this model is just like their 66 but two thirds the size. So we will call it the 99. Two thirds, see?
Fictional Singer Dictation Taker: Model forty-four, yes sir. . .
Fictional Singer Executive: No, no, two-thirds of sixty-six.
Fictional Singer Dictation Taker: *sigh* Model ninety-nine, sir.
...
Fictional Singer Executive: No, we are done with this sub model number nonsense. New feature, new model. Ninety-nine with reverse will be twice as useful as the original, so it will have double the number.
Fictional Singer Dictation Taker: *waits...*
Fictional Singer Executive: It will come to me. . .carry the one. . .no, carry the eight. . .Model 185.