INCFARM topcode flag

The description of INCFARM says “The topcoded components of INCFARM are OINCFARM and INCLONGJ.”

However, the flag tab of INCFARM shows TINCFARM as top code flag. OINCFARM does not have a top code flag.

Is this a mistake or a deliberate choice? (If the latter, why does it differ for OINCWAGE and OINCBUS which both have a quality and a top code flag?)