I agree it is not normal for Windows but is how the programmer has set the installation to work. I believe the logic is so non windows administrators can install the software. Which doesn’t make sense to me as someone who has the authority to determine what software is used for a companies accounts, will also be able to get access to their PC administrator password.
However as a result, the software can be easily installed in any location the current user has write & execute permission as described in Install or update desktop edition on Windows. The installer does not support windows User Account Control (UAC) so to install the Manager in “C:\Programs (x86)\Manager” with all your other windows software, the installer has to be run from an elevated command prompt see Windows Installation (not portable) - #6 by Patch