Do not compare bottom-line totals until the quotes describe the same home, property, route, work, quantities, responsibilities, allowances, exclusions, milestones, corrections, warranty, and closeout evidence.
Short answer: To compare manufactured-home quotes, normalize the exact home and specifications; property and site assumptions; freight, delivery, route, and access; setup, foundation, support, anchoring, marriage-line and crossover work; utilities and trades; decks, steps, skirting, drainage, cleanup, permits, inspections, corrections, warranties, and final records. Then compare quantities, materials, performers, contracting parties, allowances, exclusions, by-others work, possible repeated scope, payment milestones, changes, schedule assumptions, and completion evidence. A lower or higher total does not explain the difference until those boundaries match.