All of the performance target columns (i.e. Conversion target, CPA target or ROAS target) that can be seen on the CLIENTS tab of your control center sheet are in-month performance targets. This means these are metrics that you would like your accounts to be optimized towards in any given month.
In the case of CPA and ROAS targets specified on the control center sheet for each of your accounts, the same specified CPA and ROAS values will be used by the automation scripts when making optimization adjustments. For example if you are running a script with a CPA optimization strategy; the same specified CPA value will be used no matter the analyzed time range.
In the case of the CONVERSION optimization setting, it is a bit different to CPA and ROAS. As the Conversion target that is specified on the control center sheet is an in-month target - our scripts (when set to conversion optimization) convert that in-month target (average of 30.42 days) to an adjusted target based on the chosen timeframe. So for example, if the in-month conversion target is 100, if using a 30 days analyzed time range setting; then any entity over/under 100 conversions will have their bid adjustments increased/decreased based on that threshold. If using a 7 day analyzed time range setting, then any entity over/under 23 conversions will have their bid adjustments increased/decreased based on that threshold.
The recommendation when using the CONVERSION optimization setting is to set a lower number; as using a higher conversion target number will result in a lot of things being under the conversion target. The majority of our users optimize towards CPA/ROAS, but a significant portion of our users do prefer to optimize using conversion thresholds (i.e. if it is difficult to determine CPA/ROAS targets).