yes of course the level switch is in the oil tank.
yours is an electrical issue but now you are questioning usage?
check your pump setup...the pip and the peg at the pulley align with closed throttle, the stroke increases if you turn the pulley by hand to its stop.
If you really want to check usage
Brim fill the fuel
mark the oil tank level with a pen mark
add a known amount of oil in litres (say 300ml)
ride the bike and record all fuel added untill this mark is again reached, including one last brim fill of fuel.
calculate the ratio of fuel to oil
There is a bleed screw at the top of the oil pum and it's always a good idea to remove it al let a little oil flow out while watching for any air bubbles...replace if none.