Some detailers in USA told me business trucks and vans come always extremely dirty and filthy.
Is quite often company vehicles are not cleaned by employees, especially when driver is changing frecuently.
At the beginning I started charging double for that. I have problems with those "customers" because they said it wasn´t so dirty. And later on, they expected a perfect and shiny car after 3-4 years neglected.
I ended up not cleaning vans and commercial vehicles. I now focused on retail market. I am happier seeing happy customers.