Heroes of Might and Magic V [Game Discussion]

Question for those who still have the original manual. How much mana does a Necromancer regenerate when using Spiritual Link in versions 1.0-1.6? In version 3.0, it regenerates 1 unit of mana for 75 units of health. When playing through the original campaign in version 1.5, my Markel didn't have any mana problems. But in version 3.0, they arose even when clearing his own island at the very beginning of the 3rd mission. And that's with Markel being level 20 (skill level 6).