I just realized I was using a totally outdated version of the planner. Here's the code for the latest version (v2.4.2):
erp=IO3DJJu16N47AYzFwO6s/w7SnKn4CNY4rks076a2YPthdAxjUyrOBa2nTVydQjLkg8m7TeNBqeurF5dEluUD
Also, I wrote a short Lua script to go through all the possible on/off cycles and pick out the best ones for this design and it found the cycle of 19 seconds on and 17 seconds off to be best. Testing it in the planner gives an output of 1790.23 heat.