Consider the following

A and B only indicate that the number of lanes is increasing/decreasing. They dont show that another road is connecting to them

Connecting road in a separate lane (F20)

"The sign is specific to the conditions at the location. In case of a temporary re-routing of traffic, the sign may have an orange base. Otherwise, no deviating colour may be used."

Connecting road in a separate lane (F20)

Connecting road with acceleration lane (F19)

"The sign is specific to the conditions at the location. In case of a temporary re-routing of traffic, the sign may have an orange base. Otherwise, no deviating colour may be used."

Connecting road with acceleration lane (F19)