When you say flushing with chemicals, I wont say its required. The only thing I would consider is if you have a direct injection engine, you might need to consider removing carbon build up through walnut blasting.
Chemical flush cant guarantee 100% cleaning compared to walnut blasting. Not really considered a "flush" but still considered as removing waste.

Only certain workshops offer that. Most common cars I see using the service is x70, tiguan, and cx5.