If honda has checked everything was okay (assuming you are talking about when you went for fluid replacements), how come the TB needs cleaning now just after 3 months. Its a 20K kilometer service job. I doubt your car drove 20k in 3 months.
TB cleaning was essential in older EFI TB's where the IACV gets clogged. The DBW's adjust themselves on the go. And what Honda dont want to disclose is that even if the ECU cant accomodate that gunk on the throttle plate, its a 10 min job to reset TB calibration and allow it to re-learn.
But if they tell that to the customer, who would come and pay 2500 each time for TB cleaning??
Makes sense right
P.S. Regarding injector cleaning, yes it may work great. But I have been to a popular Injector cleaning service in Lahore multiple times for the job, they use extremely diluted chemicals (not the specified concentration) which defy the purpose of ultrasonic cleaning.
Also, no one shows you the before and after spray patterns. They just show you "AFTER" pattern and you cant judge how wrong your spray patterns were before and whether the job actually did something???