Maltodextrin is a different kind of dextrin than the dextrin found in Benefiber or CVS SFS. Maltodextrin is as easily digestible as the sugar glucose.
The dextrin in Benefiber is made from wheat starch while the dextrin in CVS is made from corn starch. These dextrins are indigestible and that is why they are used as SFS. I believe both dextrin are made by Roquette and sold under the product name of Nutriose. Novartis - the vendor of Benefiber - and CVS likely get their dextrin from Roquette.
If the dextrin in Benefiber does not give you problems it is quite likely that the dextrin in the CVS SFS will be okay too.
Try it and tell us how it goes.
What is the name of the CVS SFS with corn dextrin? I cannot find it on their web site.
-------------------- STABLE: ♂, IBS-D 50+ years - Science of IBS