Socioeconomic disparities in old-age mortality are usually assessed with indicators based on a fixed ``old age'' threshold such as average life expectancy at age 65. Interpretation of trends and determinants of these indicators is challenging because of the substantial change in the proportion of the population surviving to these ages over time. We propose the modal (i.e. most frequent) age at death as a promising indicator for social disparities at older ages. This paper examines long time trends in occupational disparities in modal age and compares these trends with those in average length of life at age 65 and 75. The modal and average lifespan indicators are estimated using Finnish mortality register data and the flexible smoothing P-spline technique. Results show that, unlike life expectancy indicators, the modal age allows comparing individuals with similar survival chances and that occupational disparities remained relatively stable over time.