Two tests, AN3 and AN4 from the RISOE-III Fission Gas Release (FGR) project are analysed using the updated version of the FALCON MOD01 code coupled with the GRSW-A model. Based on comparison of the stand-alone code calculation with the measurement for centerline fuel temperature, the previous calibration and verification of the thermal analysis of the code is confirmed. Additional analysis with the FALCON-to-FRELAX (F2F) coupled code system is carried out and presented for simulation of the effects of delayed axial redistribution of the released fission gases in the rodlets, as an attempt to interpret the data on significant jumps in measured upper-plenum pressure at a power dip. The other feature of the data, addressed by the additional sensitivity study with F2F, is peaking that can be seen in the measured fuel temperature after each power rise. A conclusion can be proposed that the peculiarities in the online-measurement could, probably, result from the features of fabrication of the fuel segments for pre-irradiation in the NPP, and instrumentation of the rodlets to be tested in the research reactor. Therefore, these features can have only limited effect on evaluation of reliability and safety of the standard fuel during normal operation in power reactors.