HR and power zone discrepancy

I tried to search the forum but couldn’t find if this has been already covered previously.

I’m currently on the 18W SS plan. After the initial test and setting up the power and HR zones, I’ve noticed during the intervals there is quite a bit of discrepancy in the Zones. My HR is always lower i.e. if I’m riding in sweetspot according to Power, my HR stays in lower Tempo or even high Z2. If I go up to HR SS zone, I need to push FTP and even over it

Should I focus on riding purely according to power and let the HR be what is, or should I modify the zones? and if so, which one, HR or W?

Heart rate can be very complicated and can have many variables. Honestly chances are is that your heart has just settled a bit as you get into shape. If you had just come off a break chances are during your field test your heart rate was some what inflated.

Go off of power. If power is showing tempo and the effort is feeling like tempo it is probably a tempo effort. If the effort is feeling lower than a tempo effort chances are your power and heart rate maybe lower and you may have improved on fitness.

So long story short just go with power but also perceived exertion.