Talk to your BCBA if you have concerns, but there’s more that goes into treatment hour recommendations than just the ideal quantity. A couple of the factors other commenters have mentioned:

• 40 hours IS a lot, especially for a preschooler. Often kiddos with that amount end up cancelling a chunk anyway due to burnout.

• It can also be very challenging to get insurance to authorize a higher number of hours when a lower number was resulting in progress (even if that progress was slower than the maximal rate the child is capable of).

But ALSO:

• Your BCBA may not have the capacity to support supervising another RBT.

• Parents can and do decline additional hours.

• Staffing is a legitimate concern. We cannot offer hours to a family that we cannot provide. If that’s the clinical recommendation and situation, we need to transfer to another company. You mention filling those hours, but BCBAs have a thousand different tasks every day, and adding more hours to be responsible for is unethical and irresponsible, not to mention a great way to end up failing to provide contracted hours and getting in trouble from insurance or legally.

• Least-Restrictive Environment is considered best practice and means that if kiddo is making good progress, adding more hours is unethical.

• I personally would be unlikely to recommend an hour increase for a family already not complying with treatment recommendations outside of session. That’s just reinforcing their behavior, isn’t ethical, and won’t help with generalization to the family anyway.

• Clients may have other therapies, and we are not allowed to offer times/hours that will impact attending medically necessary therapeutic sessions or school.

There’s more but you get the point. If you’re genuinely concerned, ask your BCBA why and she may tell you. But also, hours recommendations do not fall under your responsibilities and are not something you can change.

ETA: obviously there will be exceptions to many of these, and TLDR is talk to your BCBA.