giddion - from the game's online help manual (http://www.tresebrothers.com/star-traders-4x-empires/game-manual#Morale) - hope that helps. So, at Morale 4, you'd be looking at, I believe, +30% Maintenance cost.
Morale represents the general attitude among the star system’s Population towards the Senate and Factions – from happy and motivated to enraged and rioting. Unhappy systems are less productive and cost more to maintain, so it is to your benefit to keep your people happy. Insufficient housing is one of the biggest causes of Morale loss.
If your star system’s Morale is at 7, your maintenance rate is unaffected (100%) by Morale. Below 7, your maintenance begins to increase. At 8 Morale, your system’s maintenance rate is 90%, at Morale 9 your maintenance rate is 85% and at Morale 10 your maintenance rate is 80%.
Spice Halls are critical to keeping Colony Morale high which will reduce maintenance cost for all Colony Upgrades and is critical to defense during Xeno invasion. Spice Halls also produce critical Research Points for your Empire.
Can you elaborate on the bonus a Spice Hall provides during invasion?
Can you also confirm the %% listed in the first post related to colony maintenance and morale? I have been editing it with the information you have been providing.
Each Point of Morale below 10 provides a 5% penalty for your Defense vs. Invasion by Xeno. At 1 morale, you have a -45% efficiency rating that is applied last, after all other bonuses and penalties are calculated.