I checked the difference in position of the Imx mirrors before and after the chamber was pumped.

I used the vacuum pressure sensor channel (HVE-LY:Y1_120BTORR) to find the times were the pumped was performed.
Then, to check the difference in position I used the times:
Before: 	2014/08/05 09:00:00 UTC
After: 	2014/08/07 10:00:00 UTC

The table shows the count difference (before and after the pump):

Difference			
        L (counts)	P (counts)	Y (counts)
IM1	10	                7.42	         -7.76
IM2	-5	               -10.6	           38.8
IM3	-27	              -21.2	           9.7
IM4	4	                31.8	           38.8

The DAC is 18 bit , which gives us a maximum of +- 131072 counts (2^18 /2 = 262144/2) in OSEMS basis (UL, LL, UR, LR).
Right now, the maximum number of used counts is 116600 (H1:FEC-104_DAC_OUTPUT_0_5), which give us a free range of 14472 more.

	UL	        LL	         UR	        LR
IM1	133.0	5.4	         -0.4	        -128.0
IM2	-425.8	-243.6	241.1	423.3
IM3	-272.3	92.1	        -105.6	258.8
IM4	-59.2	-605.7	607.7	61.2

To recover the position had it before the pump, we need a maximum of 425.8 counts.
The next table shows, in counts, how much is needed to recover the original position.
 
I am attaching the spreadsheet used for the calculations and the times series plots.