In Mark 15:25 crucifixion takes place at the third hour (9 a.m.) and Jesus' death at the ninth hour (3 p.m.). However, in John 19:14 Jesus is still before Pilate at the sixth hour. Scholars have presented a number of arguments to deal with the issue, some suggesting a reconciliation, e.g., based on the use of Roman timekeeping in John but not in Mark, yet others have rejected the arguments. Several notable scholars have argued that the modern precision of marking the time of day should not be read back into the gospel accounts, written at a time when no standardization of timepieces, or exact recording of hours and minutes was available, and time was often approximated to the closest three-hour period.
Why do scholars say the times are different depending on the gospel it's written in?
based on the use of Roman timekeeping in John but not in Mark