How do we keep spacing between numerical characters equal when incrementing?



I have noticed on many pebble timer apps that the spacing between numeric characters will change slightly as they are incremented. This seems to be the default behavior of text placed on a single text layer. Normally it is barely noticeable but if you are dealing with an app that is incrementing at sub-second rates then it introduces an obvious (and undesirable) jitter. On the official pebble stopwatch app, this jitter is entirely absent. How are they achieving this result? Are they going to the trouble of placing each character on its own text layer, drawing the characters out in a graphics context, or is there a way to format text within a single text layer so that the spacing remains invariant?