The Belgian 2nd reserve IDs lacked a fourth, weapons, battalion in their Infantry Regiments and had no divisional AT or mortar companies. This meant these divisions had no organic AT guns.
The GHQ gave orders that T13s could be allocated to the 2nd reserve divisions.
Corps HQ in some cases used elements of divisional AT companies both towed and T 13 to give AT support to their 2nd reserve ID
e.g. 15/5/40 V Corps allocates 1 company of towed and 1 of T 13s split equally between its 13th and 17th IDs. the T13s initially come from the PFN T13 company
e.g.17/5/40 IV Corps allocates the T 13 company of 8 ID: half to 13 ID half to 17 ID
12 ID given 3 T13 from PFN's T13 company
15 ID given 3 T13 from PFN's T13 company.
I would be interested in finding other examples.