Backfilled data that IB provides is not tick. It is OHLC 1 min, and MT represents it by splitting it into 4 "ticks" - O, H, L and C ticks. Because of that, the representation of data as a volume chart with the candle volume that is on the order of 1 minute volume is not accurate. If you try something like 10,000 contracts, it would be better.