Thanks Linas:
1. Absolutely no issues. Just thinking about the fact my oil is 15 years old and have been there for 138000km. I do not believe in "filled for life" statements from any manufacturer.
2. No, not really. But they claim no bad experiences in the past and have done hundreds of flushing jobs, including other Toyotas, but no Lexuses so far.
They say they spend between 12 and 14 litres of fresh oil during flushing procedure to make sure all old oil and chemicals gets flushed out.
Alfalfa:
Thanks for your input. Good to hear. I asked my local Toyota workshop, but they just answered "Not necessary. No recommend intervals from Lexus."