Changing Data bundle on Orange

Presently have: Web 200 mins + 500text Ext P

and the following:


200foc extra talk min for life

FOC Text Extra 1000

Orange World Access 25

Web 100fixedminsforlife promo



I want to change the Orange World 25 to Orange World 10. However, I notice
on the Your account section at the bottom of the page it says:

"Please note that when your new bundles are activated you will lose any
messages due to you under your existing service plan"

Surely changing the data plan won't affect the Messages and talk time
bundles (which were part of the offer when I took up the plan; the 25Mb
Orange world was an extra I took on)

Tim