Whmcs changing price on a package or product

Bulk Pricing Updater

This utility can be used to apply system wide price changes to existing clients' product, addon and domain services.
This is necessary because by default, changing the pricing of products, addons and domain TLDs in WHMCS does not cascade to existing clients. That is, existing customers always remain at the prices they were shown and agreed to at the time of placing an order. The only exception to this is if you enable Product Prices Currency update setting under the Automation Settings.

Manual !

The cron won't update them.
You will either have to
1) update each one individualy
2) use the admin addon "Bulk Pricing Editor" to update all of them at once

, !
Bulk Pricing Editor