My gripe is primarily with pricing. I have no issues with parcels and all.
There's no real difference between letters and 'small packets', they're both treated/sorted and priced (almost) the same way. TLDR: It's Rs 27 for 20g and Rs 44 for 40g, to the US.
Letters are priced in bands of 20g, with Rs 20 for the first 20g and Rs 10 for additional 20g, this is the base pricing. For small packets, the pricing band is per 100g, with Rs 60 for the first 100g and Rs 45 for an additional 100g. Effectively, it's Rs 5 cheaper per 100g after the first 100g compared to letter. This pricing, whether letter or small packet, has a limit of 2kg.
Then there's air surcharge added. For the North America, it's Rs 7 per 20g. All international mail is Airmail these days. So for a 20g letter it's Rs 20 + 7. For 40g, it's Rs 20 + 10 + 7 + 7. Registered Post surcharge is Rs 70 on top of this.
These are the air surcharge rates per 20g for other regions:
SAARC - 2
Gulf - 3
Other Asian Countries - 4
Europe - 4
Africa - 5
North America & Australia - 7
South America - 9
However, recent hires at the post office computerized billing counters aren't familiar with 'Ordinary Post' or this pricing at all. It's only the veterans in the sorting room that know about it these days, which is probably why you were given such expensive options with astronomical delivery times. It's a pain to try and explain every time, so I just calculate at home and drop off in a post box instead.
We regularly send books to people across the world.
Book Post or 'Printed Papers' is a protected category that is slightly discounted by India Post. It's also given a high priority over Letter/Small Packet, in my experience (I primarily sell Indian prints of books).