Combat techniques were divided into 3 stages. The first was absorbing the energy, processing the energy and finally releasing the processed energy.
Take the Raiju breathing technique as an example. The first stage of the breathing technique synched his breathing rhythm with the lightning part of nature, enabling him to absorb lightning energy.
In the second stage, the absorbed energy was distributed to all parts of his body, increasing the power of his lightning spells.
At the third stage of the combat technique, due to the Raiju breathing technique's specialty, the released energy bypassed most of the physical defenses and went for the target's internal organs.
The third stage of combat techniques was where most of the difference lay due to their uniqueness, but Zirrack wasn't focused on the 3rd stage but on the 1st and 2nd.