Substractions in macros not working properly

I am experimenting with macros for a custom game system and encountering a weird behaviour. The macro I am trying to make takes into account the number of attacks made and compares it to a specific target to return the number of hits.

The macro is as follow :
&{template:default}{{name=Shot}}{{Sucess= [[{?{# of shots ? }d100}<?{Aim}+?{Weapon bonus}+?{Range bonus}+?{Cover}+?{Maluses}]]}}

In most cases, it works just fine and returns the correct number of successes. However, I found that, since the cover attribute is always negative (so the number is inputed as -20 for example), it causes a bug when the attribute right before it is lower than the subtracted number.
So 4d100<50+0+0+-20+0 for example does not work but 4d100<50+0+20+-20+0 does work.

Example :

Does anyone know what can cause this behaviour and if there is a way to work around it ?

Hi Tetsudo, 

I am not seeing a bug here. 

In your first example, you have 0 successes, then you add 20 and subtract 20. Thus it stays 0 successes. 
{51, 60, 92, 55}<50 is 0 successes then you add +0 +20 -20 +0 to get 0

In your second example you have 3 successes, then you subtract 20. Thus you have -17 successes. 
{76, 20, 16, 30}<50 is 3 successes, then you add +0 +0 -20 +0 to get -17

What should it state? 

Hi Gauss, I understand the logic as to why it says to me there are -17 successes but what I want is the number of d100 that are below the entire operation on the right.
So for the one where there is a problem, what I want is the number of d100 below (50+0+0-20+0) so below 30 so what I want is essentially 4d100 < 30 but without having to manually add and subtract the different factors.
I tried grouping the factors inside a parenthesis without success so I'm a bit lost.

Weap the entire calculation for the target number in inline roll brackets:

&{template:default}{{name=Shot}}{{Sucess= [[{?{# of shots ? }d100}<[[?{Aim}+?{Weapon bonus}+?{Range bonus}+?{Cover}+?{Maluses}]]]]}}

Tetsudo said:

Hi Gauss, I understand the logic as to why it says to me there are -17 successes but what I want is the number of d100 that are below the entire operation on the right.
So for the one where there is a problem, what I want is the number of d100 below (50+0+0-20+0) so below 30 so what I want is essentially 4d100 < 30 but without having to manually add and subtract the different factors.
I tried grouping the factors inside a parenthesis without success so I'm a bit lost.

Ahhh yeah, so you want to group all the modifiers to the right of the inequality. Scott's solution is the one you want. 

It works, thank you both.