Mostly, no. Some products are sold at higher concentration intended for mixing eg NPA and if you need to dilute something down to make it usable eg young guys buying 2x TUTH by mistake or P75, which often works best at tiny doses, then yes, cologne is a viable solvent.
Another option is that once you have your doses/mix worked out, it can be convenient to make a couple of days worth in a togo and add some scent to carry with you but more generally, its a minefield and unless you know your baselines, it can be very wasteful. Layering wins hands down in all other situations.