Breeder times are estimates only for the most OPTIMAL of grow conditions ( which most growers wont be able to duplicate ) . Some so called 55/60/65 day strains , for me get pushed out to week 9 or sometimes 10. Sativas can push out farther .
Go by triches only. Determine clear / milky ratio and start to monitor. It can change daily.
Some strains won't show amber or won't show yellowing leaves ( near harvest ) either.
Also , you can partial harvest the tops ( if more ready ) and leave mid / lower buds to continue swell and maturity.