Opportunity Fire modifier question

[bbrophy75]

Would the +1 column shift for opportunity fire at personnel unit apply if the target was loaded on a transport, such as a truck? Would it be any different if the target was loaded on an APC (understanding only X results would matter)? 

I couldn't find anything definitive in the rules, other than rule 5.6:

Once loaded the transport unit and everything it carries count as one unit for stacking, movement, and combat purposes.