COLTT can't be re-installed on top of existing installation

[michelpons]

I am trying to install a COLTT 2.3 commit 318 on top of an existing COLTT 2.3 installation (revision number beginning by 17D6A6D2). I am in Win 7 Pro 64 bits machine with admin rights. I get the message: "Another version of this product is already installed. Installation of this version cannot continue. To configure or remove the existing version of this product, use Add/Remove Programs on the Control Panel". I don't see this as necessary. Being warned that another version exists is fine (but does not occur for example when COLTT 2.2 is installed and COLTT 2.3 installation is run). But I don't see why an end-user would have to uninstall COLTT 2.3.XXX in order to install COLTT 2.3.YYY.