optimum plunger speed

I've got a NH 1425 self-propelled baler.  In the manual it says "During operation always leave the throttle in the forward-most position so the plunger speed remains constant at 93 strokes/minute."   Elsewhere it says, "For best results operate the baler so the plunger speed is as high as possible without exceeding the 93 strokes per minute maximum."

 

I'd like to know why a high plunger speed is important.   It seems to me (naively) that a fast plunger speed would only be important if you wanted to make bales faster.   I typically have rather light windrows and my machine makes nice bales when I run at half throttle, which saves fuel and seems much easier on this tired old machine.

 

 

 

 

optimum plunger speed