Company ID limited to registered companies in BLE

[czlucius]

The company code is limited to the registered companies for the manufacturer-specific advertisements: https://btprodspecificationrefs.blob.core.windows.net/assigned-numbers/Assigned%20Number%20Types/Assigned%20Numbers.pdf. There is no company code for small-scale applications, which means technically, one cannot use manufacturer-specific advertisements without using another company's/ an invalid company code.
What company code should we use then if we were to use this library?

Or shoud the library be sending out service data advertisements with a data type code of 0x16 instead? (GAP_ADTYPE_SERVICE_DATA), i.e. using addServiceData instead of addManufacturerData?
https://developer.android.com/reference/android/bluetooth/le/AdvertiseData.Builder#addServiceData(android.os.ParcelUuid,%20byte[])

https://stackoverflow.com/questions/62927135/android-ble-is-it-possible-to-add-service-data-and-manufacturer-data-at-the-sam
(it seems that setting both fields produces undefined/odd behaviour)

Thank you.