I think I found an Adjacency Bonus bug, please halp

I am working on my early game, and find that when I hover over the Land Fac building a Mantis it shows -3, but my Resource Bar shows a -4 despite being adjacent.
I test this between all Fac's, and have found even wilder results when producing 3 L.A.B.'s, i see -16 mass when without adjacency they'd be -15... but with they *should be -12.

please help me understand.

Some have mentioned a 'rounding' effect, but the mass pool itself is being affected quite actually in accordance to the +/- that it's displaying.

Kinda confused, thank you for you help!

Just wrong rounding really, one is most likely rounding the number to closest higher whole number, the other to lower.

so, by trying to get adjacency using 3 land factories each bumping up against 1 extractor, in my attempt to get LESS mass cost per tick I'm actually using MORE mass to build these units?

my mass bar, the FINAL result, shows I am losing mass when I shouldn't be...
rounding doesn't quite cover what I'm seeing.

building 3 LAB's costs 16/tick... WITH adjacency, which is MORE than what they'd be if I had -no- adjacency.

I'm so confused on this, this is a bug right? or is it that the game is... intentionally flawed?

The UI displays "wrong" numbers, because it truncate the numbers instead of rounding up.
Mex adjacency gives something like a 10% discount, so for a mantis that drains -4/sec, it will show -3/sec while the true result is something like -3.6/sec.
But don't worry about it, everything is working as planned, despite what the UI can display, you can verify that by just looking at your mass bar and watch how much total mass your unit costs.

Now few reminders about adjacency and gameplay :

• Mex adjacency gives tiny amount of mass discount, so it's not really mandatory to alwys build adjacent. Sure, it's free mass (it's like a free t1 mex every 5 factories you build adjacent), but you don't need to obsess about that. Better learn how to properly balance eco, and when to upgrade t2 mexes for example.

• Pgen adjaceny is useless on land facs, it only gives significant discount when adjacent to air facs, so you really don't need to do what's on your screenshot.

Bonuses can be calculated.
https://wiki.faforever.com/index.php?title=Adjacency_Bonus

But remember that for Nukes, quantum gateways, antinukes, t4 aeon arty and maybe for some other weird things numbers might not be correct

my mass bar is -16 when building 3 LABs. how does this adhere to the math you're describing please.

even setting up experiments, where my mass should be positive, i'm seeing mass TAKEN - when it should be at least fractionally positive.

from the desire to be quite thorough, let me describe the math:

What should be: 5/tick for a LAB, building 3, with adjacency should do this,
(5*.9) + (5*.9) + (5*.9) = 13.5
( 4.5 ) + ( 4.5 ) + ( 4.5 ) = 13.5

apologies, it's not 12 but 13.5, so rounded up should display -14 on the bar right, as it uses only whole numbers?

I'm seeing -16 on my mass per tick, quite literally 16 mass per tick is being taken from the pool.

This is where I'm having the disconnect.

as another direct test,

7x T1 Extractors + COM == 15 per tick
3x Land Facs, each producing a LAB w/ Adjacency == 13.5 per tick

I should be -gaining- mass, but instead it's showing a loss of 4 per tick. -4 is on the display, and my bar is shrinking.

https://replay.faforever.com/14460407

It's working as inteded, it's just not showing correct numbers.
A lab costs 35 mass and is built in 6 sec. So it drains 5.8 mass/sec, and not 5/sec. That's what i've just explained, the UI displays truncated number so 5.8 is shown as 5. Just look at your mass bar, it's not really decreasing, you still have ~700 mass.

Eeeeesh

5.8 eh??
That's a big difference. Okay. Thank you