You are settings 2 encodings, so in Chrome/Firefox with VP8, it means 2 spatial layers with 3 temporal layers each one, meaning that Chrome may send spatial layer 0 and 1 and temporal layer 0, 1 and 2.
So you are mixing the number of encodings (spatial layers) with temporal layers, which does not make sense.
Please rephrase your question. And also check your producer.getStats() (in server side) to see how many streams your browser is sending at a given time (the browser may stop sending spatial layer 1 due to CPU load, etc).