Why do schedulers put cost in a resource called cost instead of using the cost fields?

you MUST have resource to assign costs. The cost has to be assoicated with a resource and the resource is assigned to that activity. You can make a resource call it LUMPSUM if you want and assign that resource to your activities and then put in the approprate costs.

not ture you can have a SPECIFIC RESOURCE calendar its a shared resource calendar

here is a work around in your calendars create your project calendar that you want to use on your project make it unique maybe put the project number or project identifier in fromt of the calendar name i.e. 5 days per week make it DCA 5 days per week where DCA is the project name or 123456 - 5 days per week where 123456 is the project number. Then select To Global now you can select this for your resource and you can assign this back as a project calendar.

the key is making the name of the calendar unique which realtes to a project. 

Hi Raphaël,

what do you mean by "global cost resource"? in Primavera P6, I only know "Manpower", "Equipment" and "Material/Item" resources.

is a "cost resource" a resource costing $1 per hour, or something like that?

Thank you,

Alexandre