Plyos (every four weeks increase load)?

In the diagram posted in cfts. Which includes a scheme plan for ems/ 4 week cycle ect…ect…During the 12 week main build up phase. I have noticed that there seems to be increase with plyos every 4th week followed by maintenace until the next increase. Is this correct. Could you expand further on this.

Sometimes the plyo numbers rise slightly when other loading is reduced- what could be described as a loading oportunity. All adjustments are made in sufficiently small increments that stiffness can usually be avoided.

Also- when the plyos rise in the fourth week, the total intensity vol drops more than the plyo vol rises.