Sony SLV-998HF Operating Instructions Manual page 76

Checking/changing/canceling timer settings (continued)
When the timer settings overlap
The program that starts first has priority and the second program starts
recording only after the first program has finished. If the programs start at
the same time, the program listed first in the menu has priority.
76
Additional Operations
Program 1
Program 2
Will be cut off
Program 1
Program 2
about 20 seconds
about 20 seconds will be cut
off