Reduce your export time by collapsing multiclilps

Just went to export a 30 minute prores sequence with current settings and it said it would take about half an hour. Seemed excessive as there were no effects applied. The sequence consists of a 2 angle multiclip. When I collapsed the multiclip, the export time dropped to about 18 minutes.

Can someone else confirm this and whether it will also effect render times on multiclips