The back (east) side of the roof is a shed dormer for most of the length of the house. Roof is roughly 12/12 pitch with kneewall height of about 40 in. on the front (west) side. The leaks tend to be located under or near windows, skylights, and along the transition to an attached garage where there is step flashing.
The holdback is a percentage of either the manufacturer's suggested retail price (MSRP) or invoice price of a new vehicle that the manufacturer repays to the dealer. Some car buyers try to use dealer holdback to calculate the net price of a vehicle to the dealer, with the intention of using that amount as a basis for negotiating a rock-bottom price.
A callback is often back on the level of the original caller. In computer programming, a callback is a piece of executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at some convenient time. The invocation may be immediate as in a synchronous callback, or it might happen at later time as in an asynchronous callback.