Then we will make our choice on attacking #64 or #120.
In the search of #64 you will find several points with x-coordinate with the leading 60 bits = 0. You could use them here as jumps to save space (or to use more jumps in the same space). But in this way you can't reuse the old DPs.
Why paths are important and why not adding DP without computing paths ?
Using only DP:
It is like drawing a random number in a reduced space N/2^dpbit so time to solve will be O( sqrt(N/2^dpbit) )
However, it is true, that you can reach a DP faster in this way by computing consecutive points.
Using paths:
It is like drawing a bunch of 2^dpbit random points at each DP, so time to solve is O( sqrt(N)/2^dpbit )
The "gain" using path is 2^dpbit while without paths, the "gain" is only sqrt(2^dpbit)
So even if reaching a DP without path is faster, the gain is not enough to beat path.
I think that a DP worth is equal to the length of the path you computed to find it.
If you find a DP with 25 bits = 0 after 2^27 steps, that point should be worth like 4 points, each with 25 bits = 0 and found after 2^25 steps. It is like a DP with 25 bits = 0 is equal to a DP with 27 bits = 0.
If you reuse only the DPs you found after 2^27 steps, you will have a better ratio "space occupied / chance to find a collision"