LAX_LHR, if you look at the seat count on seatguru.com and compare them with what Lufthansa's own pages says, there is a difference. For the A319 seatguru specify 122 seats and Lufthansa official states 138 seats - and this difference is 13% higher at Lufthansa. The differences are less for the A320 and A321, but we may well have found the 11% increased capacity.
Source:
Lufthansa ® Germany - Seat maps and technical details of our fleets
Sorry I don't see that is relevant.
LH say the 319 is a 138 seat aircraft because it has 138 seats. But it clearly shows that in the first 6 rows the middle seat isn't used making it a 126 (not 122) seat aircraft. Therefore unless business is being dropped from MAN that that will not account for the 11% increase.