it sounds like this known issue in SMC 5.10.0, from https://kc.mcafee.com/corporate/index?page=content&id=KB85589:
126356 - Issue: Importing Network elements (Host, Networks and Address Ranges) from CSV (comma-separate value) file or a TSV (tab-separated value) file fails.
You see the error: Failed to read import <file> Details: Import failed.
It is fixed in version 5.10.1.
What formula is used to create csv for tcp/udp services and other elements to be able to import to SMC?
CSV/TSV has only support for importing network, host and range elements. XML is used for everything else, if you export some service from SMC you can open the zip and check the xml what it looks like. If you want to import some custom service from XML then just modify the file.
Though if you plan to do a lot of that, it would probably be easier with the SMC API. Reference guide is here: McAfee KnowledgeBase - McAfee Next Generation Firewall 5.10.0 SMC API Reference Guide, and the SMC ISO also has API documentation and examples.