NONMEM Level 2.1 Update

I finally got around to updating my NONMEM Version IV Level 2.0 to 2.1, PREDPP Version III Level 1.0 to 1.1, and NMTRAN Version II Level 2.0 to 2.1. I would have liked to use updated files from a disk but for some reason I did not get one with the Newsletter #11 of November 1994. I used the Fortran Workbench editor of Microsoft Fortran Powerstation. It went pretty smoothly. I compiled all altered files with the following statement: ...nmiv\run> fl32 /c /G4 /Ox /Op *.for There were the ususal warnings which I ignored but no compilation errors. I tested the udates with a problem which I ran back in December: ADVAN2 TRANS2, 1284 data records, and 158 subjects. I was surprised to see the iterations take a faster path to exactly the same minimum as before. The final parameter estimates were the same for all THETA's, ETA's, and EPSYLON's. The standard errors were, however, slightly different (mostly in the third digit, sometimes in the second). Also the correlations were slightly different. Is the faster (steeper) descent a common phenomenon with these updates? I would welcome that.