Mr D seems to be - deliberately - preventing their drivers from earning more

Mr D seems to be - deliberately - preventing their drivers from earning more. On more than 10 occasions I’ve suggested to them to allow users to enter a custom tip amount or at least provide a 15% option. If you order food for R350, you can only tip 10% or 20%. This means you can either tip R35 or R70. What if you want to tip R50? They have a 5% option, then 10% and then jump to 20%. The scary thing is that it’s been like this for as long as they have been around. Doesn’t say much for their ability to innovate or improve technologically. What worries me is that they simply ignore all suggestions or requests. Arrogance? Incompetence?