Hi Bhagwan,
1/1/5 - present. Won last race, SP > $10. ALL Aust races.

All races --- 5980 bets - Strike rate 3.54% - ROI 62.55%
Current race 1180m - 1220m --- 1221 bets - SR 3.27% - ROI 60.19%
Last race 1180m - 1220m --- 1109 bets - SR 3.69% - ROI 65.01%
Both races 1180m - 1220m --- 435 bets - SR 3.67% - ROI 71.26%
Both races 1180m - 1220m - 7 days since last race - 23 bets - 1 winner at $17. (that should give someone an ideal opportunity to shoot down my figures and say what about so and so who won on such and such paying this amount?)

Looks like your specialist theory is correct boosting the return to 70% plus. I'd say just limiting it to the current race being 1200m wouldn't work because you would have horses who won their last (longer) race returning from a spell at (an unsuitable) 1200m.

KV