Adjusting 3.30 for a 3.45 time

Adjusting the 3:30 for a 3:45 time :

"Hi Marius

We have been using the program for 4 weeks now. We felt that the intensity levels/pace in intervals in the 3.30 goal time just a bit beyond us. We changed the the intensity levels by making them half way between the 3.30 and 4.00 pace to give us a 3.45 goal time.
Is there any problem with this? Or do you suggest something else?
Many thanks
David & Jo"

Answer:Hi David & Jo and thanks for your question.

You are correct in your approach - since you are running on time in each workout, you can just find the middle times to aim more specific for a 3:45 time. Some perfer to just pick either the 4:00 or 3:30 one, and then run on heart rate to get a 3:45, and base that target on their half marathon 4 weeks before, but your approach is more specific, which is perfecly fine :)

I wish you all the best,
Marius