both offer not same functionality, and cannot say that it is older model and expensive
PA-Y10, combine output is 56.5W
USB-C Output: (PDO) 5V 3A, 9V 3A, 12V 3A, 15V 3A, 20V 2.3A; (PPS) 3V–16V 3A
USB Output: 5V 2.1A
PA-Y11, combine output is 48W
USB-C Output (Power Delivery): 5V 3A, 9V 3A, 12V 2.5A, 15V 2A, 20V 1.5A
USB-A Output (Quick Charge 3.0): 5V 3A, 9V 2A, 12V 1.5A
PA-Y11 dont have PPS, but with QC, why an iPhone user needs QC
PA-Y10 have higher output for USB PD @ 20V 2.3A => 46W + 5V 2.1A => 10.5W, total 56.5W
but PA-Y11 USB PD @20V 1.5A => 30W + 12V 1.5A => 18W, total 48W
if you have laptop can charge with USB PD, you will see PA-Y10 more useful, because some laptop can takes in 45W, where PA-Y11 will not gives enough current to laptop through USB PD which max out @ 30W
Thanks for the summary! Yeah, in the end I guess it's just a RM10 difference between the PA-Y10 and Y11, which is rather insignificant.