HikaSerial - Upgrade expiration problem/question

-- HikaShop version -- : 4.6
-- HikaSerial version -- : 4.0.1
-- Joomla version -- : 3.10.10
-- PHP version -- : 7.4.29

Hello,
Please see image

Elaine, my example user, purchased a subscription 15 days ago, for 30-days at $14.
she still has 15-days left on her current subscription.

The user wishes to upgrade, so she purchases an upgrade to her subscription for $18 for an additional 30-days.
The new purchase only adds an addition 15-days to her current subscription.

As it stands now, the individual is losing 15-days of video services.

I wish the subscription to:
1. add an addition 30-days to the end of her last subscription.
2. and at the same time, give her the ACL of the upgrade from the date of purchase to the end of the subscription (30 + current 15 days).

QUESTION
Is there a fix for this? as i do not see an option to either 1) combine time or to 2) add time from the end date of the previous subscription, for upgrades.

An additional example is the user purchase a 30-day subscription. 2-Days in, they want to upgrade, therefore they lose 28 days.
Depending on the type of upgrade (horizontal or vertical) - there should be an option to either combine the dates or to extend the dates from the initial date of purchase.

I believe this problem is on our end as all orders were deleted from the system.

Hello Jerome,
Please view the attached images.

I created a new subscription see image: Membership Subscription Detail :: order id 109
20 minutes later I upgraded my subscription. No time was added to the previous order (id 109).

Hello Jerome,
What is the approximate date I can expect the update, as I will need to change my layout to the new version.
Thanks,
Wrina

Hello Jerome,
You stated to let you know if I could think of another mode for subscriptions.
Please let me know if this can already be done.

I need a mode, that expirers when the initial subscription expires; that must be assigned to a subscription that already exists (create or renew); that is not assigned a duration nor time period; and, whose price can be $0.00.

Ex: We have a 30-day subscription but whether the user is 2 days, 10 days, or 20 days into the subscription the "new mode" should expirer at subscription expiration.

User Case Example: We are offering a video course. Once a user completes their assessment, we want to allow them to view additional video segments without cost, based on their score. We also want the "upgrade" to only last as long as their current subscription.
If we just change the ACL, the user will have access to additional videos after their subscription expirers.
And, we do not want to have to manually change every user's ACL - and we may forget to change the ACL after the subscription expires, which means users would view the data without paying or offering a donation.

Creating an ACL that allows access to a product subscription seems to be the best way for us to handle this situation.
Please let me know if there is a more efficient process.

Thank you,
Wrina