Unfortunately, you are totally confused :(
the only way you actually lose any money on the manor as a castle lord is if you OVER buy the seeds...
Wrong. The systems works like this (supposing you are castle lord):
1) You pay 10% off base seed price to produce it (money are taken from castle vault at 6am)
2) You get full amount of money person pays for seed (seed price, money are put to Castle Vault after a manor day), that is, you make money selling seeds for any price (you can sell seeds for 60%-1000% off base seed price)
3) You pay full amount of money person gets resources for (crop price, money are taken from castle Vault at 6am)
4) You get 90% of bought crops to clan warehouse
5) You craft items paying castle crafter in cash (money are taken from your own inventory).
6) You sell item.
now to buy the fruit is no loss at all just a temporary tie up of funds . but when you are getting things like enchant weapon scrolls from the fruit it would quickly make the temporary locking of funds to buy the crops more then worth it ...
For sure manor is a profitable thing for castle lord, otherwise noone will bother about manor. You can easily make like 100 million profit a week with the help of manor.
in fact if you didnt risk the losses of any seed sales and were able to buy all the fruit harvested from the other castles you would actually end up even farther ahead ... in fact I would think that having fruit in peoples inventory's would actually be a loss to a castle lord everyday ...
Wrong. Seeds in people inventories will increase chance for enough crops sold to mano lord.
so again I say why not try to buy 4x the fruit back ?
They can't. There is hard limit on crops buyback per manor day for each seed. For example, dion manor has hard limit of 4666 Blue Coda crops bought per manor day. Manor lord can't set up manor for a day buying 12k Blue codas.
Generally, limits are set according to castle and seed/crop price. Crop with twice as much base price will have twice as low limit.
Manor production depends on the same factor. So you can craft equal amount of items out of each seed with one exception.
Exception: there are two types of crops - ones for enchant scrolls and ones for anything else. You can't craft enchant scrolls using Blue coda and you can't craft QHP using Golden coda.
How can people having fruit in their inventory make any money for the castle lord ? he would make more money not selling any seeds and just buying fruit for the item profits ...
Wrong. Manor lord makes moey selling fruits. A quick example for you.
Once upon a time I've decided to put alternative seeds in play.
It was a though decision, since nearly noone wants to farm them :( Fortunately, there was a person in my clan who wanted to farm the seeds.
I wanted to increase chance for him to buy mentioned seeds to harvest.
So I've set up seed price for alternative great codran to 1000 adena and put like 3000 alternative seeds for sale (it's enough for like 2-3 days of seeding for the person).
After manor maintenance I've found out that all seeds were bought by some fool. I can't name the person buying seed other than fool, since I have not set up crop buyback for this seed type at all.
Moreover, the mentioned fool completely bought another alternative seed type for another 3 million.
So I've made like 6 millions profit not even bothering about crafting, selling etc. Just for a record, you don't make that much through crafting of mentioned seeds (crop limit allows you to craft about 1 enchant weapon A per 4 days of manor wth full buyback).
If people will buy all overpriced seeds and sell all underpriced crops, manor lords will be just happy. Fortunately, internal concurrency among manor lords in addition to moral aspects of manor system makes things a bit better than that.