I feel your pain.
Tire sizing is crazy. I have a 28mm Continental 4000s and 32mm Gatorskin that have are the same size.
And, a pair of 28 and 25mm Michelin Pro4 tires that both measure 27mm. I bought the 28 to replace the 25mm because I wanted more volume....
My 38mm & 40mm Maxis tires above measure 34mm and 37mm.