Did some more digging in Smola. There are various topics in the last half of the book. There is a table listing the 1st, 2nd and 3rd 'Goellers". This would match Kevin's supposition above. As in Geert's excellent snippet, there are two separate terms: the ricochet and the Goeller. The Goeller being at longer ranges. From Geert's piece, the Goeller would appear to be used for firing at massed infantry at a greater range, using a greater powder charge.
I will e-mail to you several pages from Smola this evening. Should be there for a breakfast read!