EC145 helicopter pilot noted what appears to be a company policy to delay documentation of certain aircraft discrepancies until parts become available to conduct necessary repairs.

Narrative

Two maintenance items were identified with a medical helicopter. First; the Mast Moment Indicator (MMI) started to lag behind the actual cyclic inputs. Second; the rotor brake was losing its effectiveness.... I noted the same problems with the MMI and the rotor brake I had observed during my previous duty week. When we returned to our base; I asked about both the peculiar indications on the MMI and the effectiveness of the rotor brake.... I then asked how it was possible that [Maintenance] could know about the MMI and the rotor brake and that no one had made note of the discrepancies in the Daily Maintenance Record. [Maintenance] replied something to the effect that we can't write up everything.... The discrepancies were noted and corrective actions were performed on [a certain date] so that tells us that something was; in fact; deficient with both items. The Daily Maintenance Record does not reflect reality because it indicates the discrepancies were identified for the first time on that date; when every pilot and mechanic knows that is not the case.... There is a safety culture problem at some bases where the front line mechanics tend to postpone and/or improperly defer maintenance issues until such time as the parts and/or tools required for the repair are on hand. In most cases; the discrepancies/irregularities are not documented in the Daily Maintenance Record until such time as the mechanics make the repair.