How did you get timings in MISC register? From below I could deduce that first byte is trpwra and last bits in the last word (4-5) are trp. Now the only place where you can have trprda are bits 19:16, so you can fit trfc between bit 15 and 5 (which is probably 7 or 8 bits, I don't know as I don't have specs), but:
1. none of the values makes sense to me compared to 146 and 160 values
2. there's still a part left in bits 23:20 that changes between your straps - what is it?
Just a little perl script I wrote to allow me to test changes easier.
$ perl strap3 -c tredc:3 -c ras2ras:160 -c rp:44 -c wrplusrp:52 -c trcdr:24 -c trcdra:24 -c trc:70 -c trfc:160 -c actrd:24 -c rasmactwr:56 -c rasmactrd:45 -c trp:10 -c trpwra:51 555000000000000022CC1C00CE596B44D0570F1531CB2409004AE7000B0314207A8900A003000000170F2E36922A3217
REGISTER KEY VALUE NEWVALUE
ARB1 actrd 23 24
ARB1 actwr 15 15
ARB1 rasmactrd 46 45
ARB1 rasmactwr 54 56
ARB2 busturn 23 23
ARB2 ras2ras 146 160
ARB2 rp 42 44
ARB2 wrplusrp 50 52
PMG seqidle 7 7
PMG seqidless 0 0
PMG tcke 12 12
PMG tckemsb 0 0
PMG tckepulse 12 12
PMG tcksre 2 2
PMG tcksrx 2 2
PMG unused1 0 0
RAS trc 68 70
RAS trcdr 22 24
RAS trcdra 22 24
RAS trcdw 14 14
RAS trcdwa 14 14
RAS trrd 6 6
RAS unused1 0 0
CAS tccdl 3 3
CAS tcl 21 21
CAS tnopr 0 0
CAS tnopw 0 0
CAS tr2r 5 5
CAS tr2w 29 29
CAS tw2r 15 15
CAS unused1 0 0
CAS unused2 0 0
MISC trfc 146 160
MISC trp 9 10
MISC trprda 11 11
MISC trpwra 49 51
MISC unused1 0 0
MISC unused2 1 1
MISC unused3 0 0
MISC2 faw 10 10
MISC2 pa2rdata 0 0
MISC2 pa2wdata 0 0
MISC2 t32aw 7 7
MISC2 tredc 2 3
MISC2 twdatatr 0 0
MISC2 twedc 7 7
Old Strap => 555000000000000022CC1C00CE596B44D0570F1531CB2409004AE7000B0314207A8900A003000000170F2E36922A3217
New Strap => 555000000000000022CC1C00CE616C46D0570F15334B050A006AE7000B0314207A8900A003000000180F2D38A02C3417