PUT for Security Center Sub Assessments

I want to push custom security assessments to Security Center/ MDC.

For the regular assessment type this is supported and works pretty cool:
https://docs.microsoft.com/en-us/rest/api/securitycenter/assessments/create-or-update

However the data structure of sub assessments is much more flexible (allows easy grouping, Severity can be different for each entity, much richer options to store details). Unfortunately Sub Assessments do not support PUT:
https://docs.microsoft.com/en-us/rest/api/securitycenter/sub-assessments

From my perspective it makes sense to expose this part of the API to end customers. Is there any plans to support this or any reason why this should not be possible?

Start with the linked Security Center assessments and sub-assessments REST API documentation, then inspect how this repository represents those API specifications. Determine whether the requested PUT operation is supported by the service and where its definition would belong; completion would require an agreed specification change and validation.

Written by the indexing model from the issue text.