RobotStudio event

Why are there so many similar FC instructions?

In FC manual: https://library.e.abb.com/public/bde123851c3c419580ee0512a055df98/3HAC050377 AM Force Control RW 6-en.pdf
There are four FC instructions
FCPress1LStart
FCPressL
FCPressC
FCPressEnd

In RobotStudio, there are additionally
FCPress1L
FCPress1C
FCPressLEnd

I see FCMACHINING module in the controller view. Is there any documentation to these three commands that are not included in the manual?