Gaps within the packet

[FishAI]

Hi all,

I have a (possibly theoretical) question:

If the message length, which indicates the slot of the checksum, is greater than the PDL plus 24 bytes, could the packet contain gaps?

Using E1.20 - 6.2.3 as an example:

0 | StartCode | SC_RDM
1 | SubStartCode | SC_SUB_MESSAGE
2 | MessageLength | 26 //Not 25 as given in the example
...
21-22 | PID | STATUS_MESSAGES
23 | Parameter Data Length (PDL) | 1
24 | Parameter Data | STATUS_ERROR
25 | <gap> | 0xff //Example value
26 | Checksum High | Checksum also contains the <gap> value
27 | Checksum Low |

I know such a packet wouldn't make much sense in practice, but is it prohibited by the standard? If so, where is this stated?
Should such a packet be processed if the checksum is still correct?

Thanks!