Additional information. An example is given.

At 93% approval the production bonus should be 25%. The previous turn, the approval was 95%, so the production bonus was 40%. Let's look at the math. Manufacturing has a 33% AllocationPercentage.
ApprovalMod-Old & multiplicative:
(11.27 * 0.3333) * (1 + 0.40) * (1 + 0.85 + 0 + 0 + 0) = 9.73 (M)anufacturing
ApprovalMod-Old & additive:
(11.27 * 0.3333) * (1 + 0.40 + 0.85 + 0 + 0 + 0) = 8.45 M
ApprovalMod-New & multiplicative:
(11.27 * 0.3333) * (1 + 0.25) * (1 + 0.85 + 0 + 0 + 0) = 8.69 M
ApprovalMod-New & additive:
(11.27 * 0.3333) * (1 + 0.25 + 0.85 + 0 + 0 + 0) = 7.89 M
So ApprovalMod-Old & multiplicative is what the game is using to come up with these numbers. And ApprovalMod-Old is whatever that bonus was at the end of last turn, regardless of whether that bonus changed to due growth-related approval changes, or if it changed due to allocation-related approval changes.