That Toyota service manager is probably driving a Toyota with the DPF taken out, he knows the real way to deal with them.
I bought a 5 year old taxi for 14,000 euro and my biggest bill fixing it was 1000 euro (new DPF which only lasted 1 year) and there is nearly 360,000 miles my car now. If I ever have DPF issues again with a car, its coming out and n0t being replaced, that 1000 euro was a total waste of money.
haven't had a DPF warning in 3 or 4 years thankfully and I will never have one again on it even if I get to 500,000 miles.