multiple DES cipher same plain

[superhansi]

atom that what i thought and thats why i think there might be a problem in the compare for same PT (salt) and -m 14000
i know the complete PT and run against a list of CT's like so:

CT : PT
1343C4EF18EEC1AE:0123456789123456
15A4E8CC064F65D9:0123456789123456

however speed drops from lets say 200gh/s for single pair to 180 with these 2, with every added pair it goes down further. When using RTX the speed drop is not that much

can you please give me a hint/idea what to try changing?
Thanks

@Kryczek comparing 1 or 15 shouldnt impact speed that much imho

edit: adding some numbers..
with 1:
Speed.#*.........:  338.3 GH/s
Recovered........: 0/1 (0.00%) Digests

with 2:
Speed.#*.........:  302.2 GH/s
Recovered........: 0/2 (0.00%) Digests

with 4
Speed.#*.........:  252.4 GH/s
Recovered........: 0/4 (0.00%) Digests

i further assumed it should get close to the hashrate with less digits left (assume one left), thats not the case either - probably because the compare algo remains inc_comp_multi_bs?

I'm having a hard time finding the right place to change / adjust