Scale the Model to a Reasonable Range of Units
Try to model your problem such that the units involved are of similar orders of magnitude. If the largest number in the model is greater than 1000 times the smallest number in the model, LINGO may encounter problems when solving the model. This may also affect the accuracy of the solution by introducing rounding problems.
For example, consider a financial problem with equations expressing an interest rate of 8.5% (.085) and budget constraints of $12,850,000. The difference in magnitude between these numbers is on the order of 10^9 (1/100th compared to 10,000,000). A difference of 10^4 or less between the largest and smallest units would be preferable. In this case, the budget could be expressed in units of millions of dollars. That is, $12.85 would be used to represent $12,850,000. This lowers the difference in magnitude of the units of these numbers to 10^4.