Oneworld.com's planner permits 17th segment for origin-destination.
Luckily our side

According to the xONEx rule:
Travel may originate at any point for which fares are published and must terminate at the same point,
except that origin-destination surface segments are permitted as follows
(a) within the country of origin

A minimum of 3 and maximum of 16 segments, including surface segments between any 2 airports,
are permitted for the entire journey.

However, 17th segments as an origin-destinaion surface segment is not counted for 16 segments maximum.

At least, oneworld explorer planner treats an origin-destination surface segement differ from surface segments.