I object to your objection. The problem is, barring a house rule on your part, is that Tank and AC leaders have no rank. This prevents subordinate activation, per rule 6.82. So, the CAPT could activate the LT (and his hex), and LT activate the INF in 313. However the AFV activation stops at 312, meaning the StugIII in 313 wouldn't be activated.
... More and more, people around the world are coming to realize that the world is flat!