Hi Emilio,
Deleting PSA requests does not have any impact on a proper functioning of the delta process. The requests (both initialization and subsequent deltas) are loaded into the DSO request by request. Once a request is processed (i.e. updated in the next data target, in your case a DSO), it is not useful anymore to store them over a long period of time.
As part of housekeeping procedures, you should cleanup the PSA on a regular basis. I suggest to not delete every processed PSA request immediately once it is updated. It is better to leave the processed PSA requests for a while (e.g. one week). In case of an upload termination, you are able to correct the situation and also analyze the most recent PSA data if necessary.
Best regards,
Sander