This Smath document is worth 2 pieces of gold: 1. a much higher Smath numerical integration. 2. numerical integration of splines [ainterp] cinterp => not tested. As it looks, it would be easy to rebuild the Smath integrator.
... the great Smath "Integrate Companion" for your toool box 1. almost 12 decimals garanted 2. integrate the "splines" directly 3. added the "incremental splines derivative [order 1].
Done in Smath 5346 OFFicial release, must be checked latest release.
...my collaboration about "Integration" seems to end here. There is surely a way to universalise the "Maple Procedure". Hopefully, this Smath document answers all past & future questions. Maple Procedure will not solve all cases, for instance: if Maple returns a function that Smath does not have [Polylog, Bessel ...] the Procedue will fails.