I really feel you on this, it can be quite worrying when they get referred out after the assessment. I don't have the exact figures for NUH speech therapy costs and session details on hand, so I wouldn't want to give you the wrong numbers. I'd suggest calling NUH's Children's Outpatient Centre directly to ask about fees, session length, and frequency, as these can vary depending on your child's needs and whether you qualify for any subsidies. Hang in there, getting the referral early is actually a really good thing for your boy.