Does the placement of a low-flow pump within the well screen matter?

I have a former gasoline station site with a couple of wells screened approximately 0.5 to 1 foot below the top of the water table. If using the low flow sampling method, and the tubing is placed approximately 3 feet below the water level in the well AND we know that LNAPL is not present at the site, would sampling results for petroleum hydrocarbon compounds be representative of water quality from these samples?

Several sampling studies have shown that, in essence, pump intake location within the well screen zone does not greatly affect target analyte concentrations when wells are purged at low flow rates. When the well is pumped, it lowers the hydraulic head inside the pipe from the head outside the pipe and water flows from the formation anywhere that it can along the length of the well intake. The contribution of  water to the screen is controlled by the geologic materials surrounding it. Zones of higher hydrologic conductivity, or high K, will contribute more water, while lower K zones contribute less. Field studies and numerical models have shown that, regardless of the pump intake position within the well screen, sample results should be comparable and will represent a flow-weighted average concentration of the target analytes with sufficient purging to establish stabilized purging indicator parameters measured at the well head.