Level flight is of little consequence to CDA, as suggested, but is relevant to the need for careful and accurate management of the vertical profile, as has been suggested elsewhere.
Also, ICAO Doc8168 quotes in vectoring to the ILS for parallel approaches”:
“The vector shall also be such as to enable the aircraft to be established on the ILS localizer course or MLS final approach track in level flight for at least 3.7 km (2.0 NM) prior to intercepting the ILS glide path or specified MLS elevation angle”.
This would seem to indicate to me that some element of level flight is mandated for such operations. Y/N?