(7-72b) Purchase Cost Discounts From Different Sources Stack Multiplicatively

[axatin]

Counterproposal to (7-91) Change how "purchase cost reduction" abilities work

As pointed out in the OP, additive modifiers are an issue because their combined effect can be too strong. However, the proposed replacement ability "gold costs are more effective" cannot be understood without knowledge of a formula which is impossible to guess or derive from the description. We shouldn't replace an effect that's easy to understand with something obscure. Currently there's a wild mix of additive and multiplicative modifiers (see spoiler below), and a better solution to the problem would be to make all modifiers from different sources stack multiplicatively and to change the descriptions accordingly.

Proposal:
Global modifiers from buildings, global modifiers from policies, and local modifiers all stack multiplicatively. Rialto district is changed from "-10% purchase cost in all cities, -15% in capital" to "-15% purchase costs in all cities". That's a slight buff, but it compensates for the fact that Rialto doesn't stack additively with stock exchanges and industry any longer.

As a result, we have the following sources of purchase cost reductions that stack multiplicatively:
- Stock Exchange (local building)
- Forbidden Palace and Rialto (global buildings)
- Industry (policy)

The Industry policies still stack additively with each other, as would be expected. The only other possible source of additive modifiers is the combination Forbidden Palace and Rialto District, which is unlikely to occur.

The description for Industry stays as it is: "-5% Gold needed for purchases." That's the typical way additive modifiers are described in Civ 5.
The description for the Stock Exchange is changed to "Purchasing Items in this City requires 20% less Gold". That description makes it clear that the modifier stacks multiplicatively with any other modifiers that might be in effect. The same wording is also used for the other buildings.

This also makes it consistent with how the modifiers to building costs only and to unit costs only are handled: Both of them already stack multiplicatively with the general modifier.

Spoiler Current modifiers :

Modifiers for purchase costs of buildings and units:

• Forbidden Palace: -15% global
• Industry: -30% global in total
• Stock Exchange: -20% local
• Rialto District: -10% global, -5% local

The local modifiers stack additively with each other, the global modifiers stack additively with each other, but global and local modifiers stack multiplicatively. Example: If we have Industry and a city with Forbidden Palace and Stock Exchange, the local modifier is 1-0.2=0.8 and the global modifier is 1-0.3-0.15 = 0.55. Total purchase costs are then 44% (0.8*0.55 = 0.44) of the original value.

In addition to that, the modifiers that reduce purchase costs for buildings only (Communism) and for units only (Military-Industrial complex) both stack multiplicatively with the above.

 

[Stalker0]

I think you need to show an example or two for the audience to make it clear what your changing. Not everyone is a math head

 

[azum4roll]

The description for the Stock Exchange is changed to "Purchasing Items in this City requires 20% less Gold". That description makes it clear that the modifier stacks multiplicatively with any other modifiers that might be in effect. The same wording is also used for the other buildings.

I don't think it's anywhere "clear". In fact, if I haven't seen this and start doing a sweep on building text, I'd have changed this back to "-20% Gold needed for purchases".

MIC and Communism only stack multiplicatively because they're entirely different concepts (hurry cost reduction vs building/unit purchase cost reduction).

 

[axatin]

Sponsored

 

[Recursive]

Timestamp post to arrange all the threads in a neat order.