It's a bit complicated, but the below should do the trick with CB Auto Actions. Gave it a quick test and confirmed it works to push the paid amount to a field.
Code:
UPDATE `#__comprofiler` SET `FIELD_NAME_HERE` = ( SELECT p.`mc_gross` FROM `#__cbsubs_payments` AS p WHERE p.`payment_basket_id` = ( SELECT i.`payment_basket_id` FROM `#__cbsubs_payment_items` AS i WHERE i.`subscription_id` = '[subscription_id]' ORDER BY i.`id` DESC LIMIT 1 ) ORDER BY p.`id` DESC LIMIT 1 ) WHERE `id` = '[user_id]'
Change FIELD_NAME_HERE to the name of the field you want to set the value into. Set the above to both Activation and Renewal. What it's doing is taking the subscription id and grabbing the latest payment basket item associated with it. It then grabs the latest payment associated with that basket and outputs its mc_gross. You'll probably need to make adjustments here though as auto recurring payments come from mc_amount, but this is a good start.
Sorry, I don't have any other solutions at this time. Anything else would require something more complex and would need CB Auto Actions.
krileon
