1.27% extension use -0.27
1.414% extension use -0.414
1.618% extension use -0.618
No need to use the FIB extension tool, which saves a whole lot of time
For all retracement levels 23.6, 38.2, 50, 61.8 I use extension level 1.618 (however you will notice on the shallower pull-backs <38.2 price often halts around the 1.27 level and comes back for a deeper retracement (80/20 rule).
78.6 pullback target 1.27 extension
88.6 deep pullback target 1.18 extension
Hope this makes sense and why I colour code the fib retracement lines with the extension levels (RED to RED)