The setting “200 000 x units” allows to view the maximum amount of historical data available for the security you are looking at and the chosen time frame. It is therefore possible that for some time units there are less than 200 000 units displayed.  As already outlined by @Despair and @verdi55 the 6 minute chart is based indeed on 1 minute data; therefore, the 6 minute chart has less data available than the 5 minute chart (which goes back to July 2015).

However, some charts show even more than 200 000 units as for example the Dow Jones 1 minute chart.

Note also that major securities (this concerns especially stocks) will show a higher amount of historical intraday data than less liquid instruments.

Please click on the following link in order to see a comparison concerning the maximum amount of historical data available in the Complete and Premium versions: Premium version benefits