Objective: To evaluate baseline student satisfaction, compare service quality between two “Accredited Excellent” vocational engineering programs-S1 Building Engineering Education (PTB) and S1 Mechanical Engineering Education (PTM)-and diagnose operational bottlenecks to align empirical findings with institutional quality assurance and global educational standards. Method: A quantitative comparative-descriptive survey design was conducted with a stratified random sample of N = 422 undergraduate students (PTB N1 = 215 and PTM N2 = 207). Data were collected using a 23-indicator SERVQUAL instrument on a 4-point Likert scale and analyzed using descriptive statistics (Mean, Standard Deviation, Respondent Achievement Degree/TCR), independent-samples t-tests (α = 0.05), and Cohen’s d effect size estimations. Results: Although overall satisfaction reached a “Satisfied” baseline (TCR = 75.47%), inferential testing revealed a statistically significant disparity (p = 0.0429) favoring PTB over PTM. Granular item analysis isolated critical operational bottlenecks in laboratory equipment adequacy (P18), general campus facility accessibility (P23), and administrative responsiveness in facility loan procedures (P16). Novelty: The research shows that top-tier accreditation does not guarantee uniform program-level service delivery, offering a pioneering framework that directly integrates granular SERVQUAL diagnostics into the institutional Internal Quality Assurance System (SPMI-PPEPP cycle) and United Nations Sustainable Development Goal 4 (Targets 4. a and 4.4).