We do flex on most takeoffs, but that has no difference - we get both normal and reduced thrust numbers on the same page. For example, on the landing distance data page, it requires the following inputs:
Weight
Airport code
Rwy
Wind is optional.
Then temp and pressure will autofill if the airport publishes a METAR or D-ATIS. You can manually input these and override the autofill, and pressure will adjust the data it returns. However, when you adjust the temperature, nothing changes.