If you look at the monster kills/Essence drops required for each level of the Heroic Guild quest you will notice that they are not in line with previous LTQs. It is expected that the Heroic Mode would be more difficult to complete, this is usually done 1 of 2 ways. Either the individual monsters require more HP and energy to defeat or there is a larger number of monsters/drops to collect. During this Quest both are increased.
However it is the magnitude of that increase that points to a programming mistake. The attached picture highlights the problem.
The Normal mode Guild Quest shows the typical progression. With each progressive level requiring more Total HP to complete and more guild members to complete the corresponding Individual quest level.
However, you will notice a large jump in the Heroic Mode Guild quest. Typically, Level 1 of the Heroic Guild quest is not as difficult to complete as the final level of the Normal Mode Guild Quest. In the Twilight of Mankind Guild Quest you see an immediate jump and then continued progression from there.
In fact if you look at the number of guild members that would need to complete there corresponding Individual Heroic LTQ levels you would see that the number is roughly double what you would be expected. In fact by the time your guild reaches Heroic Guild Quest Level 9, you will need 67 guild members to complete it (I don't know of many 67 member guilds )
My assumption is that the programmer intending for Essence drops from both the Normal mode and Heroic mode to count towards the total required to satisfy the Heroic Mode Guild Quest. However, since they tagged the Heroic Mode drops with the (H) they are distinct from the normal mode drops.
Gree is the Heroic mode difficulty as intended or will you admit a mistake was made?