That $ figure tells us nothing as it includes those same huge SMS costs that Signal is on an unsustainable path to rack up
With just a bit more effort you can see that most of those $148 are not related to the extra customer support we're discussing, but rather to the things that Signal is already doing
Costs and expenses in 2013:
Cost of revenue 53 (payment processing fees, infrastructure costs, SMS verification fees and employee compensation for part of operations team)
R&D 77 (engineering and technical teams who are responsible for the design, development, and testing of the features)
So for $10M revenue, they had $53M cost of revenue. I think asking for $1 is never going to be sustainable, even if leave all other costs. My guess is that "employee compensation for part of operations team" is the primary one taking all the cost, as payment processing fees couldn't be more than the revenue itself and one message is pretty cheap.
With just a bit more effort you can see that most of those $148 are not related to the extra customer support we're discussing, but rather to the things that Signal is already doing
Costs and expenses in 2013:
Cost of revenue 53 (payment processing fees, infrastructure costs, SMS verification fees and employee compensation for part of operations team)
R&D 77 (engineering and technical teams who are responsible for the design, development, and testing of the features)
G&A 19