When used in machine-guns, these rounds are placed every 10 rounds along the belt, giving a bonus of +1 (single shot) or +2 (burst fire) to strike.
Page 110 only assigns burst damages for machine guns though, and says they are burst fire only.
I know in previous games you got a per-shot damage and then applied multipliers, and I there might have been a game where 'burst only' was not a rule and you could single-shot with machine guns.
Could this note for Tracer rounds be a leftover from that?
If not, when, if at all, would the +1 on single shots come into effect? It seems like only the +2 on burst fire is usable.