A method for reducing a composition error in the output flow of a mixing pump system, the method, for each packet consisting of a sequence of at least two fluid components in a plurality of packets provided to an intake of the mixing pump system, comprising: actuating a first valve during the packet to provide a first volume of a first fluid component of said packet to the intake of the mixing pump system; actuating a second valve during the packet and at a switching time defined as the time after the actuation of the first valve to provide a first volume of the second fluid component of said packet to the intake of the mixing pump system; actuating the first valve during subsequent packets to provide an additional volume of the first fluid component of said subsequent packets to the intake of the mixing pump system; and actuating the second valve during subsequent packets and at a switching time defined as the time after the actuation of the first valve for the subsequent packets to provide an additional volume of the second fluid component of said subsequent packets to the intake of the mixing pump system, wherein at least two of the first and additional volumes of the first fluid component differ and at least two of the first and additional volumes of the second fluid component differ, wherein the switching times of the packet and the subsequent packets are offset from one another and determined in response to a frequency characteristic of an intake response of the mixing pump system, and wherein the sum of the switching time offsets are zero so that an average of the first and additional volumes of the first fluid component and an average of the first and additional volumes of the second fluid component volume equals a respective fluid component volume predetermined to achieve a proportion of the respective fluid component in the output flow. actuating a first valve during the packet to provide a first volume of a first fluid component of said packet to the intake of the mixing pump system; actuating a second valve during the packet and at a switching time defined as the time after the actuation of the first valve to provide a first volume of the second fluid component of said packet to the intake of the mixing pump system; actuating the first valve during subsequent packets to provide an additional volume of the first fluid component of said subsequent packets to the intake of the mixing pump system; and actuating the second valve during subsequent packets and at a switching time defined as the time after the actuation of the first valve for the subsequent packets to provide an additional volume of the second fluid component of said subsequent packets to the intake of the mixing pump system, wherein at least two of the first and additional volumes of the first fluid component differ and at least two of the first and additional volumes of the second fluid component differ, wherein the switching times of the packet and the subsequent packets are offset from one another and determined in response to a frequency characteristic of an intake response of the mixing pump system, and wherein the sum of the switching time offsets are zero so that an average of the first and additional volumes of the first fluid component and an average of the first and additional volumes of the second fluid component volume equals a respective fluid component volume predetermined to achieve a proportion of the respective fluid component in the output flow.