Yes, one respondent (vendor) organization can be issued multiple invitations to the same RFP project. This allows the vendor to compile two or more sets of answers to the same questions. This can be useful for cases such as variable pricing or multiple service offerings, where the same vendor can provide a different set of data.
To help with such cases PostRFP provides a "Label" field that can be completed for each Response. This can be used to differentiate between multiple responses from the same vendor:
|Vendor A||Full Service Offering||07/09/2015|
|Vendor A||Partial Service Offer||07/09/2015|