The airbus iPad EFB shows us all possible flex temperatures. I have never seen someone massage the numbers, but quite often we take a degree, or two, lower flex temperatures to get the margin we like. As the company leased the engines on average thrust reduction we are fine, as we easily achieve that anyway. Why do pilots reduce flex and increase margin? Well, we had a runway overrun a few years back, where even a sizeable margin was of no use although the take off abort was done according to OEM procedure and well within limits, since then pilots often feel uncomfortable to use every last inch.
EFB software is not new to us though, we have been using EFBs for more than 15 years now, airlines somewhat new to this might react differently.