Hi Bryan , Unfortunately this doesn't tell us much that we didnt already know or surmise , ie that the CG is ahead of the centre of preasure of the lower wing ....Unless of course ,there's more ?.........Over to You Know Who !
A better translation might read :---
The arrangement / positioning of the " Wings " (apparatus ) is such that the centre of preasure of the lower wing is behind the centre of gravity
JM
( I would question whether the writers use of "lower wings " should not have just meant to say , " the wing cellule as a whole " ? as it is obvious that the CG /CP relationship depends on position of " both" wings )