It was mentioned in AN2515 and AN2633 that external 32k crystal typically consume more power than internal ULP OSC. But when I look at the power consumption published in DS, for example for ATtiny1614, Table 37-5. a RTC running at 1.024k from XOSC32K consume 0.69uA, from OSCULP32K it consume 0.71uA. It seems XOSC32K should be as efficient as OSCULP32K.
Any experience on power consumption of these clocks ? I want to use XOSC32K but want to avoid having to do power optimization if unnecessary.