Mind explaining the reasoning behind that? I'm trying to come up with reasons to convince myself but it's not working.
The reason is that when you start up and the SOC is low, and you decide to get moving while the ICE is in the warm-up stages, the SOC seems to drop faster when you decide to get some momentum going by giving it some gas. This is because the SOC indicator is not linear. When your warming up and stationary, more amps can go in to the HV battery than if you let the car crawl. Because in crawling, the energy coming from the ICE warming up will be split, diverted or worse sucking more energy from the low SOC state of the HV battery to get the car moving. So if you have low SOC, it's better to just stay put and absorb all the charge you can get from the warm-up cycle, even if it's really little (+1 to 1.5% SOC depending on how long it takes to end stage 2). If you have a decent charge upon start-up (usually above 52%), you could use that 2% to get some momentum to start the crawl and cover some ground which could add to the "M" (even though it's just meters) in your MPG.