Better Chiltern services for Amersham at am peak

I found this document regarding the timetable changes for the May - September period on the Chiltern Railways website:
www.chilternrailways.co.uk/sites/default/files/May%202011%20Timetable%20brief.pdf
It says:

7. Improved Services from Amersham and Rickmansworth, weekdays:
There will be an additional 0707 Amersham to London Marylebone service created by adding an Amersham call into the 0640 Aylesbury to London Marylebone.*
There will be an additional 0842 Amersham to London Marylebone service created by adding an Amersham call into the 0816 Aylesbury Vale Parkway to London Marylebone service*
There will be an additional 0838 Rickmansworth to London Marylebone service created by adding a Rickmansworth call into the 0805 Aylesbury to London Marylebone.
We are confident that there are sufficient spare seats on these three trains to accommodate the passengers from the additional calls

Also:

0626 Aylesbury to London Marylebone via Amersham: to have 90 additional seats
0713 Aylesbury Vale Parkway to London Marylebone via Amersham: to have 70 additional seats*

*Non-stop services to Marylebone from Amersham