Meljet/PSS merged - "jumping" on runway after landing!!!!

Hi, I have merged a Meljet 744 with the PSS cockpit. Now, whenever I do a landing, the plane "jumps" on the runway as if the surface were grossly uneven. My landing config should be correct: 25 flaps, speed as calculated per FMC (around 142kn dpending on LWGT), speedbrakes armed (extending at touchdown), ILS and APP mode capturedCould it have to do with one of these two things:1. just before touching down, I switch off ATHR autothrottle (to then put the thrust levers on idle, before engaging thrust reverse)2. autobrakes are on level 3Neither of these SHOULD have an impact, but you never know... ANy ideas?CheersChris