CaptPaddy
That is not quite what I am saying.
If you have a G+B Hyd failure, then the requirements of all the system implications are covered by the single QRH entry.
If you have multiple problems, you MAY have to multiply the corrections or MAY NOT depending on the combination of the failures.
Looking at the (BA) QRH, the failures with an asterisk (*) against them are:
Flt Ctl - Altn/Direct Law, ELAC 1+2, L(R) ELEV, STAB JAM, L+R ELEV
Flaps/Slats - Any failure
NAV - Dual IR Fault, DUAL ADR Fault, NAV 1+2+3 Fault
ENG - Rev Unlocked with buffet
If the combination of failures is limited to the above you take the highest factor for the landing distance, not the multiple.
If however the combination of failures is not limited to a combination of the above you must multiply the factors.
So, as in my previous reply, FLAPS + BRK ANTI SKID => multiply factors as only one is *; and if FLAPS + ALTN LAW => do not multiply as both *.
Clearer?