Hello dear specialists. On 135 coated paper, I placed a scale with a gradation of 0-5-10-20.....80-90-90-100%.I performed measurements of the scale compared according to the ISO standard, all the gains are normal, just wonderful.I decided to observe the increase for two shifts. We printed a book with a volume of 15 paper sheets. And I found that the increase of the raster point on different paper sheets is different, both plus and minus, in addition, some on the reverse side are normal, but not on the front. I wanted to make corrections on the rip for an increase and realized that there is no point, since there is no stable same value. Why is this happening? And in this case, how to standardize offset printing? Machine Speedmaster sm 102-5+lac. 70,000,000 sheets mileage.