A quote from the MW Dictionary of Synonyms (without examples here):
"Severe is applicable to persons and their looks, acts, thoughts, and utterances or to things (as laws, penalties, judgments, and styles) for which persons are responsible. In all these applications it implies rigorous standards of what is just, right, ethical, beautiful, or acceptable and unsparing or exacting adherence to them; it not only excludes every hint of laxity or indulgence but often suggests a preference for what is hard, plain, or meager (a severe teacher). Very often the word suggests harshness or even cruelty (severe criticism)."
"Harsh suggests a nature that is unfeeling, cruel, and indifferent to the pain it inflicts (a harsh critic) or when applied to things, effectiveness in promoting discomforts or in imposing rigors (a harsh rebuke)."
Compare the following examples (taken from different sources):
The country has come under severe criticism for its human rights record. [strong, neither bad not good]
Many people feel the punishment should have been more severe.
It may seem harsh to punish him, but he has to learn that this kind of behaviour is unacceptable.
He later regretted his harsh words. [negative]
He accused her of being unduly harsh. [negative]
Nothing can justify such harsh treatment of prisoners. [negative]
When you say developed by someone, it means that the product or thing was developed by that someone- the developer of the product. When you say developed by ABC, inc. it means that the product or thing was developed by ABC's staff- the employees collectively working on the product.
When you say, developed at ABC, inc. it means that the product was developed at ABC, indicating a location of the company in question.
In most cases it would roughly give the same meaning, as most products are developed both by a company and at a company. However, it's possible that the product is developed or designed by a company but assembled at a different place and by different people. For example:
The iPhone was designed by Apple in California, but it was assembled by a different company in China.
Best Answer
While "schedule in advance" would seem on the face of it to be redundant, it's a frequently-used phrase and is meaningful in the sense of setting the schedule or obtaining the reservations or whatever some significant period of time in advance (days/weeks/months) vs waiting until the last minute.