The answer depends upon a number of factors. In the most general terms, with all other factors being equal, the number of measurements varies inversely with the DCGL.
In reality, a change in the DCGL reflects a change in the assumptions used to translate dose or risk into concentration. This could affect the survey design in several ways. For example, changing the area of radioactivity in the exposure pathway model would change the size of survey units specified in the survey design. In another example, changes in the depth of radioactivity assumed by the model would change the sample collection procedures and scan sensitivity required for the final status survey design. In these cases, it is difficult to predict what exact affect the DCGL will have on the survey design.
For more information on the MARSSIM process, visit Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM).