Here is the manual to the LTv2.5
http://www.volcanoecigs.com/media/lavatube-manaual.pdf
yes it should store the settings you have your device set on and when you replace a drained battery it should turn back on to where you left it.
The initial setting on your Lavatube v2.5 device will vary from Average to vRMS mode in either variable voltage or variable wattage. When in Average Voltage mode (NO1) the power going to the heating elements will be a little higher than in vRMS (NO2) mode. For this reason we recommend only advanced users set the mode to (NO1). For a smoother, more consistent vape, we recommend the device be set to (NO2) mode. For a hotter, more intense vape, we recommend setting the device in the (NO1) mode but suggest you use a lower voltage/wattage setting than normal. This will help to prevent the heating element from burning out.
what ohm is the device you are using on the LT?