Let me breakdown the T-Mobile One plan, and you can switch over to that plan if you aren't currently on it.
The T-Mobile One plan includes unlimited talk, text, and data at 4G LTE speeds for up to 50B, at which your speed will slow down then.
Included features with T-Mobile One plan at no extra charges are explained at this webpage.
https://www.t-mobile.com/cell-phone-plansIf you have 4 lines, the online prices is showing at $160 for just the plan when using autopay, so you actually get a discount for when using autopay.
Equipment Installment Financing:
It seems like you are financing for three devices, the Galaxy S9+, S8, and a S7.
The current monthly pricing for all three devices all together is probably going to be lower than what you are paying right now, but please keep in mind that with the release of new Samsung Galaxy phones, the prices of the previous generation ones will go down, therefore what you are paying now could be higher or lower depending on when you have purchased it. Please check your equipment financing documentation.
Every line will have different pricing for services, so please check your account information.
Personally, I don't find that I need T-Mobile Jump, but it is a great deal, because once you pay off half the total value of the device, you can trade it in for a new phone, and T-Mobile will erase the remaining half that you would be responsible for. You'd only have to pay for the new device then.
Now, one thing that points out to me that you DON'T have the T-Mobile One plan, is the fact that you pay for taxes and fees separately from the plan. You might be on the older T-MUS One plan, before the inclusion of tax and fees, or on the Simple Choice plans. You might want to check that out.
International Calling Issues:
Did you include the $15 Stateside Calling feature onto your international call lines? It would save you a lot more because for $15 a month, you'll get unlimited calls from the U.S., Mexico, and Canada to mobile numbers in more than 30 countries, as well as the unlimited calls from the U.S., Mexico, and Canada to landlines in more than 70 countries and destinations and all other benefits of Stateside International Talk. Check it out here. As always, any Simple Choice or One plan includes Stateside International text automatically, at no extra charge. It allows you to send and receive unlimited text messages to ANY countries that is able to, except St. Helena and Wallis and Futuna.
if you do lots of traveling, maybe the additional $25/line upgrade to the T-Mobile One Plus International is more suited for you. It includes Stateside International Calling, as well as many other features for a more enjoyable and connected experience out of states. Check it out!
I hope I could explain everything as detailed as possible, and I hope that I've help you understand the pricings. Keep in mind that, prices advertised by T-Mobile only include the plan cost, therefore if you choose to finance devices, add special features, such as S.I.C, JUMP! or etc., extra charges will incur.
If you need the help of a T-Mobile representative, you can dial 611 from your T-Mobile device anytime, message them on myTmobile, web or phone app, or you can even reach their social media accounts. Remember, I'm not a T-Mobile representative.