The Constructive Cost Model COCOMO II and the PROxy Based Estimating model PROBE, were validated and calibrated based on short-term software projects developed by twenty one organizations at four cities in the central-west Colombian region, Manizales, Pereira, Armenia y Cali. The software development was embedded within a workshop based on the Personal Software Process PSP that last four weeks and includes work in class and work outside class. The COCOMO II statistical analysis includes the validation of the existing COCOMO II 1997 and 2000 calibrations, and the calibration of COCOMO II 2000 using CALICO. The PROBE statistical analysis produces object categories for Java and Php programming languages, regarding function and size, but cannot validate existing categories for Object Pascal and C++.