The computer grades are QFVC=A and QFEV1=A, based on the fact that there are three acceptable curves and a repeatable FVC and FEV1. The subject is a young male and reaching a plateau in 2 to 3 seconds is not unusual. In an older subject, this may be considered an abrupt termination but for younger subjects, it is likely there simply is no more air to exhale. There also is a slight variation in volumes at the end of the curves indicating the upper airways may not be completely closed. Given the repeatability of the volume-time curves and FVC values, there is reason to expect that the FVC's and FEV1 values represent the subject's maximal effort -- thus the computer grades of QFVC=A and QFEV1=A are confirmed.
