Took me a few reads to get the idea behind Combat Skill, Combat Styles and Combat Moves.
Page 20 under Combat Moves states in reference to Advanced Combat Moves( stated as 'others'):
"The others require special training, but once learned, may be learned with any appropriate Combat Skill."
So, I thought you could buy a combat move and use it for any combat skill as long as the combat move was applicable to the combat skills category, for example if you purchase All out Attack for a melee combat skill, then it would be useable for all combat skills in the melee category.
Then I read page 47, which states:
"Please note that Combat Moves must be purchased separately for each Combat Skill."
Which cleared that up.