Perf B LDR query for EASA standard
 

Performance has never been my strong point so would rather embarrass myself here rather than company.

If our AFM Landing field length required chart has a 60% factor included but our SOP's state that for EASA we must obtain this performance within 70% of LDA a reduced LDA is needed.

It goes on with an example and factors the chart result x 0.857 and is therefore less as stated. LDR from graph 3900ft=3342ft LDR

Reading it that way I would have said we needed to increase by 1.16?

Am I misreading this or getting LDA's and LDR's crossed?

Any guidance appreciated.
Cheers
SS