multiple origin of the history data from metaquotes ? i am looking for infos about the source of this history

 

i started the following way:

- deleted the hst file of the EURUSD (so no more history of other sources)

- download of the EURUSD M1 in the history center tab of metatrader 4

while watching the chart 1 found out that the history from jan 1999 to 18.9.2006

seems to be from a different source than the history from 19.9.2006 to 2008

the older history has a bigger distance of the high and low per bar

than the history since 19.9.2006

the older history has a almost constant volume per bar,

while the history since 19.9.2006 has a wider spectrum regarding the volume

i am curious about the source of the older history since it seems to provide better results for

EA backtesting (especially scalping)

Reason: