To answer your question about if the rewards increase, yes.
I have 5 Imperial floors, and the current mission I'm on awards 18,040 credits.
This does require 12 different items, so 12 supply officers are needed.
I could buy them all for 12,000 to speed it along, as waiting it out has taken some time.
You definitely get more credits than the rewards the emperor gives you, but whether that's worth the payoff to build the levels I guess is up to you.
gaming.stackexchange.com/users/4239/Doozer Blake
I currently have 73 levels out of 80, my imperial levels are 16/16.
Before they added an extra 6 levels there were only 10 which lead all the way up from interrogation to communications, I remember that I received 250k credits every time I got the required items.
I do recommend that you build them.
They will help you start out with a lot of money at low death star levels
(Please note that when I received the 250k credits, I was 80% done with the quests)
gaming.stackexchange.com/users/62418/Connor
The rewards do increase, but it seems the missions vary from person to person.
I only have 9 imperial floors and it tells me there are no more imperial missions.
WTF?
I've read of other missions that other people do that I never encountered.
There is no benefits for me to build imperial levels anymore besides unlocking new species (this seems to be the case, but not proven).
gaming.stackexchange.com/users/62384/user62384
The Imperial levels pay off well and then abruptly do no good once the quests are done and now I am just sending my supply officers down there building more and more inventory that I can't use.
I would advise not spending the 1000 credits on Supply Officers because before you know it, you will havr more of them than you can use.
gaming.stackexchange.com/users/446/Cade Roux
This response no longer applies after the 1.3.0 update
The rewards for imperial floors are calculated as follows:
((M1 * Q1)
+
(M2 * Q2)
+ (M3 * Q3)
* 51)
Where M1 is the number of minutes it takes to stock an imperial floor and Q1 is the number of items stocked from that floor.
M2/3 and Q2/3 are for subsequent floors required to redeem the reward.
Basically, for every minute it takes to stock an Imperial floor item, you get 51 credits.
E.g., one of the missions is: 15 Rebel Secrets 1 Salvage 2 Battle Plans
The total reward is 13,515 and is calculated as follows: Rebel Secrets = 10 minutes to stock Salvage = 25 minutes to stock Battle Plans = 45 minutes to stock
((10 * 15)
+ (1 * 25) + (2 * 45))
* 51 = 13,515
gaming.stackexchange.com/users/65471/rbf2000
I've just discovered how to maximise the money you make.
The "mission" that ask you to produce however many of whatever thing, are based on the number of the imperial level not really the thing they ask you for.
So since you make more money the longer an item takes to produce, use the 'level mover' VIPs to move into position the imperial level with the longest production time.
I'm only up to level 10 myself, but so far Superlaser, and Droid Lab have the longest production time.
If you those into position to alter each mission you'll rake in the cash.
gaming.stackexchange.com/users/68379/Simonmmm
I'm trying to build my Tiny Death Star as fast as possible, and I check in on it a couple times each day.  At first, I was building imperial levels to complete the missions, but the income from the missions seems pretty low compared to just building other floors.  Is there ever an increase in rewards to more coins and/or missions that give bux?
Are imperial levels worth building?
gaming.stackexchange.com
<star-wars-tiny-death-star>
gaming.stackexchange.com/questions/143167
gaming.stackexchange.com/users/58848/User
It is recommended. It will help you start out with a lot of money at low death star levels. The missions vary from person to person. It seems that imperial levels can help earning money.
The community suggests that building imperial levels can help up to a point.