It was asserted at the beginning that the 
@x-1pob-4vyb would distribute 150,000 VYB at the cost of 1 POB for 4 VYB. This means after 37,500 POB gets sent to the bot, you will no longer get 4 VYB for 1 POB and you cannot even get 3 VYB / POB. You'll have to be satisfied with 2 VYB / POB.
Exchange Rate: 2 VYB / 1 POB
It turns out the second bot was never operational. Send at least 250 POB to 
@x-1pob-2vyb and you'll get 2VYB for each POB you send. You should be able to do this so long as the sum of all of the bot's balances don't exceed 120,833 POB.
| Sum of Bot Balances Range | Exchange Rate |
|---|
| 0 – 37,500 | 4 VYB/POB |
| 37500 – 70,833 | 3 VYB/POB |
| 70,833 – 120,833 | 2 VYB/POB |
| 120,833 – 420,834 | 1 VYB/POB |
| 420,834 – 445,834 | 1 VYB/2 POB |
