Increase in running frequency (added bricks), but staying within 10%

If I increase my run frequency by adding 1 or 2 transition runs a week meanwhile staying within the 10% rule for all individual workouts and weekly volume could this lead possible overuse injuries?

The plan I'm on now currently has 3 runs and then one short transition run :20 min after the long bike. I'm looking to add another :20 min transition run elsewhere in the week all the while maintaining my long run, tempo run, and 20 sec pickup run. In order to do this I would scale back initially but then progress forward with workout times in the appropriate manner.

My 1/2 ironman is now 12 weeks away. This is my 4th year of tri's and I already have 2 1/2's under my belt.