In my case, being a much older person, with a more standard basal mind you, First thing I did was get rid of the % percentage options, and go to straight units, with the smallest being .25 full unit. not .025. The percentages never seemed right and were just too much trouble to calculate, and typically not close enough to be effective. By changing the min/max values to be higher than the mins that the PDM can take, I gained a bit more control without having to keep hitting enter to add more each dose etc.
Now, as I mentioned, I am an adult, full sized, meaning I take insulin by full units most times, but I do like and use the ability to take only a half unit or less to tweak the BG down. I am also still in the slight adjustment phase on the PDM and still adjusting the main basal by about .25 per day, per week. IE each weak I end up making a slight adjustment as I am slowly getting my normal BG down to below 180. (I Never went below that on mdi.)
Being ill, typically throws standard calculations out the window, and in my personal case I have to raise the basal by about a 1/3rd on a daily basis, and by about 3-4 units extra per meal. Each individual will require different settings of course.
Your absolute best option is to discuss with your Endo and/or your Insulet rep (if you have one that is also adjusting your insulin dosages etc, if not, then whomever professional health care practitioner is handling your PDM work with you.
Best of luck to your son, and you, in getting a handle on things. It is a learning experience for everyone I believe.
I hate being sick and managing my diabetes. Fortunately, I've not been really sick since starting on the Omnipod system. But, it seems to me that if your child's BG are "off the chart", then an extra basal from rounding up might not be bad. Definitely talk to a Doc or nurse asap.
You can change the temp basal rate parameters to use units of insulin instead of basal rate percentage. I found this after recently having a cortisone shot. I had to up my temp basal to 2.5 times the normal amount to compensate. By changing to units of insulin I was able to add an extra 2 units per hour. My normal basal is .7 and even 95% of .7 was not enough.