I have a current Program goal of “231w to 241w by 23rd May” for 5 minute power.
I am currently in the “Peak” phase however I am finding all recommended sessions very doable with only 1 High Intensity session a week.
I have marked Monday and Friday as days off.
Should I up intensity?
I find it hard to read Xert to know how well I am tracking against the goal/plan
I’m guessing you saw this on the iOS app? Forecast AI plans don’t directly have ‘phases’ like our original “Base-Build-Peak” program (formerly known as Target Event Date program). Updates are needed (& planned) for the Android and iOS apps to align them with many of our latest web app features. 
Check out the ‘PROGRAM’ tab on the web - it will show how your training loads (low, high, & peak) and your fitness signature (TP, HIE, PP) are tracking versus the Forecasted values
You could push yourself for a breakthrough and see if you can exceed your goal. If so, create a new program with a new, higher goal! If you want to do HIIT a little more frequently, you can try changing your Training Polarization from the default (4:1) down to 3:1 or 2:1, which will give you smaller, more frequent doses of high intensity.
HTH!