I assume the LTV field is a mautic custom field? How are you increasing the LTV field value with each purchase? I assume the field value is increasing form $100 to $140 with each purchase? Are u manually updating the field or is the field overwritten with the latest sale value?
Currently we are having a separate app that is updating the custom field (LTV) adding the new amount to it through Mautic API. so we are not building the logic/calculation on Mautic to be honest. its like a separate app that job is to transform the raw transaction/purchase data to a customer data (fields) that will be ready to push to mautic.
The LTV field is essentially a scoring field. Set up triggers for threshold LTV amounts. If is LTV = 10, do this. If LTV = 50 do this other thing and so on.
I am not sure Mautic can do formula driven calculations to calculate points.
I had some success integrating Mautic and a google sheet with Integromat. Maybe you could claculate the correct poit score based of the LTV in a google sheet and then use integromat to sync that result back to Mautic?