kasinkei

for the 2nd case, draw a timeline
now is time 0
starting end of this year - a withdrawal of 70K, which is indexed to inflation is happening.
and this will happen for 25 years. So your PV / FV/ N / PMT method is set up right.
If by the same token - the first 70K withdrawal had happened NOW - the 71.4K (70 * 1.02) would need to have become the PMT term for the next 25 years.