Having blocks of different rep ranges is a very well known method and works very well but I’m not sure you have it set up quite right.
In most cases there are just two blocks and each block usually last 3 to 4 weeks. The reason for this is if you have 3 blocks and each block last 6 weeks then by the time you get back to your starting block 12 weeks would have gone by and you most likely would have lost the effect of that original block.
The first block is an accumulation phase where you train your main lifts in a rep range of say 7-10 reps depending on what the lift is. Obviously not all lifts have the same rep range. This is a high volume phase also known as a hypertrophy phase.
The 2nd block is an intensification phase where you train your main lifts in a rep range of say 3-6. Again it may change slightly depending on what the lift is. This is a high intensity phase also known as a strength phase.
After completing both blocks some exercise may be changed.
These rep range recommendations are for the main lifts. You can certainly go higher on auxiliary lifts such as bent over dumbbell rows or lateral raises etc…