So for those interested, I have reversed the formula to encode the STAGE variable:
Excel formula to encode an offset:
=((MOD(Floor(<STAGE>/64,1),2^1))*64+(MOD(Floor(<STAGE>/64,1),2^2)>=2)*-128+(MOD(Floor(<STAGE>/64,1),2^3)>=2^2)*256+(MOD(Floor(<STAGE>/64,1),2^4)>=2^3)*512+(MOD(Floor(<STAGE>/64,1),2^5)>=2^4)*-1024+(MOD(Floor(<STAGE>/64,1),2^6)>=2^5)*-2048)-MOD(<STAGE>,64)+ISODD(<STAGE>)*2
This offset is then added to a fixed number -1,908,683,586
Example Values:
Stage 1 - Offset: +1 | Encoded: -1,908,683,585
Stage 2 - Offset: -2 | Encoded: -1,908,683,588
Stage 3 - Offset: -1 | Encoded: -1,908,683,587
Stage 4 - Offset: -4 | Encoded: -1,908,683,590
...
Stage 10 - Offset: -10 | Encoded: -1,908,683,593
Stage 100 - Offset: 28 | Encoded: -1,908,683,558
Stage 200 - Offset: -72 | Encoded: -1,908,683,658
Stage 400 - Offset: 112 | Encoded: -1,908,683,474
Stage 800 - Offset: 736 | Encoded: -1,908,682,850
Stage 1000 - Offset: 664 | Encoded: -1,908,682,922
Stage 1800 - Offset: -264 | Encoded: -1,908,683,850
Stage 2500 - Offset: -1860 | Encoded: -1,908,685,446
Stage 3000 - Offset: -1464 | Encoded: -1,908,685,050
Stage 3500 - Offset: -2988 | Encoded: -1,908,686,574
In theory, you can set yourself at Stage 3501 by using -1,908,686,573, but you will very likely get banned.
Hope someone find this helpful.