How to draw item with quality in slot-like sprite-button correctly?

Example:
Im trying to get electric network charge and capacity

electric_network have 2 common accumulator, 4 legendary accumulators and 10 rare accumulators

LuaFlowStatistics.get_flow_count{id="accumulator", ..., count=true} returns 2 (Count of common accumulators) (need for calculating capacity ...