variation of time values in output data

Dear nonmem users, We used the option “-2 RATE” of NONMEM (actual rate of infusion is unknown): within the control stream: D1=THETA(1) Moreover, since several infusions are given to the same patients, we have added an inter-occasion variability on D1 (see code below)* We obtained nice fit BUT in the OUTPUT DATA: TIME values corresponding to blood samples (and DV) are not identical to the actual TIME values of the INPUT data !? It seems that NONMEM program adjusts rate values, their interoccasion variability, and sampling times to have a good fit *How to fix TIME value corresponding to blood samples ? Indeed, we do not know the actual infusion rate but we do know the sampling times.* Can anyone tell me if I chose the right model or help me resolving this? Thanks in advance, *$PK OCC1=0 OCC2=0 IF(DATE.EQ.1) OCC1=1 IF(DATE.EQ.2) OCC2=1 D1=THETA(1)*EXP(ETA(3)+ETA(4)*OCC1+ETA(5)*OCC2) $THETA (0,168,);D1 $OMEGA .1 ; iiv d1 $OMEGA BLOCK(1) .01 ; iov ETA4 OCC1 $OMEGA BLOCK(1) SAME ; iov ETA5 OCC2 *Loïc FIEVET* *Interne IPR en pharmacocinétique (1er semestre)* *Institut Universitaire du Cancer Toulouse - Oncopole* 1 avenue Irène Joliot-Curie 31059 TOULOUSE Cedex 9