FXCM (UK) advertised and actual spreads are absolutely different

The above graph is a result of FXCM (UK) continuous monitoring during 45 hours. Data were collected on demo account every 5 minutes.

Series1 (dark blue) is a momentarily Ask-Bid difference and Series2 (magenta) is an average spread for last 100 ticks.

As you might see the actual results are far beyond promised (advertised) values. The minimum spread never hit promised 0.1 pip value and typical is not 2 but 5 pips.