Multiple-use calibration for future observations plays a valuable role in many fields, including health and medical research. Simultaneous tolerance bands (STBs) and simultaneous tolerance regions (STRs) can be used for this purpose. Motivated by a real-world example involving the estimation of gestational age using ultrasound measurements, this study focuses on the construction of exact STBs for polynomial regression and STRs for multivariate regression over any given covariate interval. We also develop weighted simultaneous tolerance regions (WSTRs), demonstrating that confidence sets based on WSTRs exactly satisfy the key property required for multiple-use calibration. Through the lens of WSTRs, we show that confidence sets based on pointwise tolerance regions do not guarantee this property.