Recommended pitch
Some manufacturers recommend particular pitch values
Selected pitches can have improved interpolation properties.
GE use pitchd 3 and 6 only (HQ and HS mode) on four slice LightSpeed
Toshiba and Philips use mainly pitchd 2.5, 3, 3.5, 4.5, 5, 5.5, 6, 7 (not 4)
In practice, advantages are slim, and depend on implementation of interpolation algorithms