Bankroll challenge from NL2 to NL500

I am 38 years old and playing poker for good few years mostly for fun. Recently I put some effort in studying it and I think it's time to take it seriously.

Couple days ago I started a thread about weekly bankroll challenge. Everything was fine until this morning when my hard drive died. In additional to lost PT4 database I lost nearly full day and physically won't be able to complete it. For this reason I decided to start a proper bankroll challenge from NL2 to NL500

During bankroll challenge I plan to complete 500k hands over 40 weeks and increase bankroll from $20 to $45,000. I will try to update this thread on a daily basis

Poker challenge consist of 8 steps. Each step reflects a stake. I will use progressive bankroll building starting with minimum requirements of 20 BI for NL2 and 90 BI for NL500.

Steps breakdown:

• Step 1 NL2: Starting bankroll $20. Target bankroll 20 BI + 4 BI of next stake: $60
  
• Step 2 NL5: Starting bankroll $60. Target bankroll 30 BI + 4 BI of next stake: $190
  
• Step 3 NL10: Starting bankroll $190. Target bankroll 40 BI + 4 BI of next stake: $500
  
• Step 4 NL25: Starting bankroll $500. Target bankroll 50 BI + 4 BI of next stake: $1450
  
• Step 5 NL50: Starting bankroll $1450. Target bankroll 60 BI + 4 BI of next stake: $3400
  
• Step 6 NL100: Starting bankroll $3400. Target bankroll 70 BI + 4 BI of next stake: $8000
  
• Step 7 NL250: Starting bankroll $8000. Target bankroll 80 BI + 4 BI of next stake: $22000
  
• Step 8 NL500: Starting bankroll $22000. Target bankroll 90 BI: $45000
  

Why I need 4 BI of next stake. Let say I am playing NL2. My target is 20 BI what is $40. I need 4 more BI of next stake so I could play NL5. If my bankroll goes down to $40 after I started to play NL5, I am playing NL2 again. If I am winning I continue on.