Okay, so I decided to build a simple model to answer the...

Okay, so I decided to build a simple model to answer the following question for myself.
For the purpose of discussion, anyone is free to disagree but please try to mention which assumption/point you disagree with.

What is 5G worth to Telstra in FY20 in the Retail segment?
Total Revenue (AUD) FY20: $348,095,999
Total 5G Users End of FY20: 3,449,600
Percentage of users: 44%
Assumptions:

• Telstra has 8,020,000 mobile post paid customers as of beginning of FY20. (Annual report)
• There are 180,000 Belong Customers, none of which are prepared to pay extra for their mobile services.
• Mobile users upgrade their device, on average every 3 years. (Casual Upgraders percentage 30%)
• 10% of die-hard customers opt-in immediately, as of July 2020 and begin paying for 5G. They all pay, each month for the entire year.
• 50% of all mobile users use Apple iPhone, while 50% use "Other"
• Apple release an iPhone capable of 5G in September, which is available in Australia in October.
• 20% of all iPhone users upgrade to the new iPhone Immediately. 100% of Apple Ugraders opt-in for 5G and pay for remainder of the year, starting from end of month
• The remainder of users are regarded as "Casual Upgraders" they upgrade in the middle of the remainder of the year and pay for the rest of the period
• The opt-in price for 5G access remains $15 per month for the entire Financial Year