These methods calculate a certain function over all the bytes in the layer and check the result. They do not take any parameters and make no explicit use of the current field value (with one exception, Checksum1sComplement16bit). Because of this it would be possible to apply one of these methods on any FIELD at all; nevertheless we put them only on CRC and checksum FIELDs because that is where we want a checksum/CRC failure to be signaled.
It is worth repeating that all the standard methods (with the exception of Checksum1sComplement16bit) perform their check over the entirety of the layer assuming that the last byte/word/dword (as appropriate) contains the sender's check. Should you need to verify a CRC over some sub-portion of a layer then you will need to supply a custom method for the purpose.
It is never valid to include a NOT in a VERIFY clause when using a checksum/CRC method. (Including a NOT will not generate an error but the NOT will be ignored.)