[NEST Users] Triplets STDP model

Dear NEST community, I am working with the triplets STDP connection on NEST simulations, and I am interested in how the weight dynamics change when the spike trains are altered in some specific ways. In order to do that, I run a network simulation using NEST and the triplets STDP rule and save the full spike trains of two neurons which are synaptically connected (one pre and one post). I then recreate the weight changes on a code outside the NEST loop, so that I can manipulate the spike trains and observe what happens to the synaptic weights. Trying to validate this approach, though, I find that my code (outside NEST loop) generates different weight values than the NEST simulation when using the same spike trains generated during the simulation. I guess I have some error in my implementation of the triplets rule. I thought it could be something with the implementation of the delays, or the moment when the weights are measured in the simulation, but I have had no success trying to fix it yet. I know this is not exactly a NEST issue, but I thought I would give it a try and ask here at the list. In case someone has already worked with the triplets rule and could point me out to what is/could be wrong in my implementation, I would very much appreciate it :) Thanks! best, Júlia