I highly support this recommendation.

Upon player injured, manager needed to call up the tactic change screen, select substitute player and make formation or tactic change if necessary. In T11 matches, 10 minutes represent about 1 minute in real life. If manager consume 30 seconds for above actions, the match have already run for 5 minutes. Even if the manager's reaction is lightning fast and needs only 5 seconds or even less to complete these tasks, T11 match system usually does not react immediately. It will execute this on the specific time slot. This may need further 5 more minutes if the manager is unlucky. As a result, the suffering team may easily play 1 less player for 5 to 10 minutes because of the violence behavior of opposite team.

In my opinion, such disadvantage caused by delayed substitution is also unfair element in real life football/soccer.