When creating a new free form CAN message, the default data length is 4 bytes. If this is changed to 8 bytes, for example, the end bit for the default variable in the packing section that is automatically opened remains at 31. This cannot be changed to a higher value. To access bits 32 and up, the default variable in the window must be deleted, and a new one opened.

This does seem to be a bug in the configuration tool.

However, as a side note, the database uses double values to store the data in the database. This presents an issue if you are trying to map one variable to a value greater than 4 bytes. If a value greater than 4 bytes needs to be mapped to a variable it should be split into two variables. A script is helpful for stuffing the values.

The other thing that cannot be done is to span partial bytes. For example if I want to use 10 bits, or I want to use bits 6 through 9. It allows partial single bytes or whole multiple bytes only.

This is also not possible in the J1939 section, although it is allowed under the J1939 protocol (J1939-71 sect 5.4.1 uses 10 bits in their example of bit length).