Hi K.,
I feel very strongly on this issue. I am a SLP and have worked with kids on the spectrum in California for many years. As you know, every child in the world is different, and kids on the spectrum- although having some similar manifestations, are very different. You need to be careful when you read research. Research does support more intensive therapy, but ABA is not the "golden bullet" that "cures" autism. ABA is a good therapeutic approach, and also has a lot of people pushing it. There are other valid approaches as well- such as floor-time, RDI, social stories, etc. There are also some things that are promoted that have not found to be effective. Kids with autism do need early intervention, and tend not to learn incidentally -like neuro-typical developing kids are more able to do, so do need more hours of intervention. How that intervention looks though can and should vary per child. Kids with ASD really benefit from the parents being involved in a team approach with the specialists working with the family. So some of the "25-40" hours can be with the child involved as much as possible in age appropriate toddler activities with the parent and other support as needed. It doesn't need ( shouldn't be) hours in a sterile room at a table with an interventionist of some type.
OK- I'll get off my band wagon. No, there isn't a law on how many hours of any therapy is offered. It's natural as a parent that you want the best and most for your son. If I were in your shoes, I would express my concerns to Regional Center and say how you want to be a big part of the team. Concerned and interested families are important. Are you comfortable with your case-worker? If you have a strong worker, they can be helpful in making sure whatever is available in your area will be offered for your boy. There also is a limit financially to what can be offered for people with disabilities. Your son is entitled to a "free and appropriate education"- but so are all the other kids with needs. As a SLP in the schools I can honestly say that yes, my kids progress on their IEP's, and yes I would like to provide even more service, but can not because I already have a full work-load. When parents and I can work together, and families don't expect the schools to "fix the problem", the kids reach their maximum potential. I believe that is true for all kids, whether typically developing or not. I am sure that the majority of special educators feel the same way, and experience similar situations.
Congratulations on your beautiful little boy and my sincerest hopes for a good journey together learning about your son's strengths and weaknesses as he grows and develops.