A maximum of three slider velocities should be used (including 1x). For example, you could have a single map using 0.6x, 0.8x, and 1x; or 0.75x, 1x, and 1.5x; etc. If more than three slider velocities are used, then they should make sense and be intuitive. If slider velocity changes are able to be merged (e.g. close values like 0.8x and 0.7x) while still flowing/working correctly, then they should be.The last sentence in this guideline doesn't make any sense... Why should they have to be merged? There's no problem with having them as separate values as long as they fit.
Suggestion: remove the last sentence