Your intuition is not bad. A possible solution is to take the PV as of today and compute the value as
\(2137(1+r_m)^{12} \)
The solution in the excel sheet takes a different approach and directly goes from next month present value
\(2146(1+r_m)^{11} \)
Note that the exponent is different because the present value (2146) is already next month, so we just need to move the value 11 months into the future
Got it, thanks